I think the above statement is pretty obvious really, that is what everyone wants from a photochromic, however, as we all know, performance is a trade off, its a chemical equilibrium (UV incidence vs ambient temperature) while manufacturers all try their best to optimise the system in the best matrix. What we see Tr6 doing is admitting the hot weather knocks nearly 50% off the final activation strength, and sell a system which is inherantly a lot darker and slower, angled specifically at getting glasses more tuned to hotter climate performance. This means the same system in cold weather is now far too slow, too dark and poorer residual colour indoors than a lot of people find acceptable.
On the back of this they are fragmenting their market into special leisure areas by promoting lenses specifically for golfing, cycling, fishing, outdoor frisbee throwing, horseriding and dog walking (ok, I exaggerate a little) - is this because they are under so much pressure to reinvent the wheel every year, and there is now no further they can go with the Tr6 system?