They have been instructed to not give anything away and if it is sold you must go through their Investment Recovery Department. This has mostly been caused by the perpetual litigators who use the system to sue for something they did (if) to themselves and are looking for a gravy train payout. The ambulance chasing lawyers are just as guilty in perpetrating the scams.

no it not main reason.  the big reason they want there light back.  It cause they get  some of there money back
from recycling. and some of money is been recovered.
so recycling them may cover about 10 percent of cost
of led conversion.  so if u want be on there end user
that u need to find out what scrap metal yard  they go
to and see if that scrap yard let u buy some lights when
they come in there metal yard.

Well, I guess it's good I never asked for streetlights then, because they'll just say no, which is a shame too.

The contractors over here (first time an outside contractor had been hired by the council) are obligated to all the same stuff. But they are fairly careless at actually doing this - they throw away around the place maybe 1/10 of everything they replace

I found out that if you ask them for parts or anything, they will be more careful to not leave anything around. This is in contrast to the council workers that used to be ok with you taking unwanted stuff for the most part. Yet i am not trying to discourage you from asking - especially if you dont get anything otherwise anyway

Most of the lanterns and gear i collected were from what the contractors left scattered around the place on the ground or in the nearest trash cans / dumpsters. If they are doing something like a town square then sometimes the stuff will be all concentrated in one place. The biggest things i found from them were parts of posttop lanterns (enough to assemble 3..4 complete lanterns) which they left in a particularly obscure and overgrown far end of a footpath. They just left it thrown deeper into the plants, possibly right off the top of the columns

Our power company are still with the good attitude - from the 00s when i was kid up to now

In the case of the council (not related to the power company) their original maintenance people were okay. Back in the day it was a fairly big "maintenance department" that employed all sorts of people including electricians (whose work included the lighting maintenance), plumbers, trash collecting workers, painters, welders, i think they even were the official employer of the school janitors. Since then most of those jobs were outsourced to outside contractors and some (not all but way too many) of those are quite hostile. Not only that, they do much worse work than when it was people that worked for their own town