Whay Triphosphor linear flurescent argon-krypton filled T8 & T5 lamp much more efficient then cfl with the same phosphor and buffer gas both with or without integrated ballast?
Linear - 80-105 lpw
Compact - 50 - 60 lpw like regular halophospour fluorescent tube.

1. Linear tube shape allow way much more accurate phosphor thickness
2. CFL shine in big extend into itself
3. Linear tube shape allow higher temperatures used for outgassing, so yield cleaner atmosphere.
4. Within linear tubes segment is taff competition in the commercial market, where the lamp purchase cost itself is not as significant parameter. Dominant are energy use, reliability and maintenance/handling labor costs, so the one, who offer more reliable, more efficient and longer lasting bulb win, not the one offering the cheapest bulb. Sometimes the waste management costs play a role: In EU all fluoros are hazardous waste of the same kind, so there is strong push towards long life.
In contrast in US the waste category (so the cost of handling with spent lamps) depend on mercury dose, so creations like ALTO appear, where the priority was shifted towards "ultra low mercury" category, even in the expense of short life and frequent early failures (due to too low dose).