Except for the already discontinued israeli Rapidstart autotransformer ballast of Eltam for US 110 HO T12 lamps, which was also a HPF (High Power Factor), the HPF magnetic ballasts are unique to the american market. Simply i don't know any european made or chinese made HPF magnetic ballasts for the european market.
I don't know why there is no european HPF magnetic ballasts on the market, but i think that the power factor term in fluorescent lighting are ignored and are not important in the european market (Indeed, in the copying room of the storage of Carmel hospital, a choke ballast for a 36W T8 lamp that lights the working table aren't connected to a capacitor (Only to the glow starter) and still operated perfectly). Also the americans promotes the magnetic ballasts much more then the much more efficient and environmently friendliers electronic ballasts unlike the europeans results in the presence of the HPF magnetic ballasts in the american market.
Generally, most israelis household preheat magnetic ballasts installations aren't includes a power factor correction capacitors at all.

Might it have anything to do with how power usage is metered? Only in the last few years here in the US has electric meters been able to accurately measure power usage from low power factor devices. I could be wrong about that, but the standard mechanical meters that we have always used will under-register when power factor is below 1. Again, I could be wrong, but there is now a big push to replace mechanical meters with electronic meters for a number of reasons, power factor being one of them. Therefore, power factor might not be as important here as it once was.

-Nelson

@nodgen:
Here (Czech Republic) electric meters are required to have tolerance within (+0/-2%) of apparent on the measured real power and i think 0.1% of wattage range at low loads. Mechanical meters were way better, but only when the cause of the low power factor was only the phase shift.
Actually electronic meters had quite long time difficulty to reach this accuracy generally (mainly the one at low power level), but unlike on mechanical types, the harmonic distortion does not make the error worse. These days the technology improved, so when new meters installed, they are electronic. But still majority of replacements are restored and recalibrated mechanical types (the law here require valid calibration certificate for any measurement instrument used for billing, what expires after few years, but even those 30 and more years old meters are able to pass these criteria after normal maintenance, so are still repeatedly used)
But the reason is not he accuracy or so, but available features (remote read-out, multi-tariff,...) and mainly it's own electric consumption: Mechanical meters consume about 5W (those newer ones, older types even 15..20W), while the electronic ones consume below 1W.

Most of the ballast here in the UK are low power factor copper-iron chokes and it's up to the manufacturer of the light fitting whether to install an additional power factor correction capacitor. Power factor correction is never bothered with for domestic installations as this just bumps the cost of the light fitting up, you may struggle to find a light fitting of high power factor aimed at domestic use.

You can simply wire a capacitor across the live and neutral to convert any low power factor magnetic ballast to a high power factor one, it seems to be about 1uf for every 10 watts of lamp load and polyester film capacitors are most common. This is only a rough guide though and I recommend you check first which capacitor you need.

I think there are a few reasons HPF magnetic ballasts are so common in the American market.

First has to do with voltage.  In Europe and other 230v parts of the world, most fluorescent lights operate off simple choke ballasts, where if power factor correction is needed, an external cap is easy to add.  In North America with 120v, Fluorescent lights over 25 watts require an autotransformer ballast, which usually requires the cap to be part of the ballast circuit itself instead of parallel on the outside.

I think it also has to do with the fact that the vast majority of fluorescent lights are used in commercial installations, where the combined reduction in current to all the fixtures can make a noticeable difference in the cost of delivering power to a building.  On the other hand, most fluorescent and HID lights sold for home use do not have power factor correction.

I think it has to do with the following:
Low cost ballasts use only the leakage inductance (and lower power fluorescent ones sometimes wire resistance as well) to form the necessary ballasting impedance. This lead to full apparent power being handled by at least the primary winding, what cause it to have higher losses.

While if in the typical HPF fluorescent RS ballast the transformer is designed as low leak (so would be smaller) and the capacitor is used as the main ballast impedance, then adding gap to the transformer's magnetic circuit cause it's main inductance to drop and to compensate the power factor of the capacitive lamp load on the secondary. As this compensation take place only between the core, secondary winding (what have to handle the whole apparent power Vocv*Ilamp, so ~200VA in F32T8 RS ballast anyway) and the lamp, the primary then has to carry only the real power (~40W), so might be of thinner wire (same, as used in the rest of the ballast, simplifying the manufacture) and even with this it will have lower losses.
CWA ballasts use the capacitor as main ballasting impedance (in order to let it with the saturating shunt stabilize the lamp current), so again adding a gap into the transformer main magnetic loop cause it to compensate the phase of the secondary side, again relieving the primary from carying the whole apparent power (on MH it is ~3x the lamp wattage).

On multitap HX ballasts (CWA is poorly tolerated by some, mainly modern, lamp types) the compensation capacitor is connected to higher voltage tap, so the asociated current and so primary losses are smaller then without it, so it's use save some power usage as well

But the use of the capacitor in any form make the ballast more expensive, so that whay it is not used on home grade cheap products (however i think using such cheap balasts is false economy, as the extra losses cost way more on the energy bill then is the ballast purchase cost difference)


With simple series choke ballast the use of the capacitor does not influence the ballasts losses, as the ballast voltages and currents remain the same, so HPF versions differ really only in the power factor and nothing more.

When I was in Germany back in the late 80's, I've seen many fixtures with two 36w PH lamps with one lamp using a cap in series with choke. As long as both lamps are working, the PF is high. If fixture uses only one lamp, then cap would have to be across the line of course, but I don't recall seeing those. I wonder if a cap across line can cause voltage spike during switching, thus making it unpopular.