Plenty of companies do use FLASH, and these companies usually do not have usable web sites, the have "flashy" web displays (how appropriately named flash is). The only major content provider that uses flash is youtube. The rest is marketing hype.
Product manufacturer X hires a web site designer (who is used to using flash tools and thinks they are therefore easier to use than anything else), to design a fancy looking website that satisfies the VP of the small product line company. These companies don't even know that their website is unusable, because their website is not used. But at least the VP thinks they do not have a 90s era web presence.
Their website is not part of their business model, others sell their products to consumers. If the website were part of their business model, it would not likely use flash (except for the adds, since they don't really care if that is a hurdle to their users, they get paid anyway). Even on windows, users need to install flash to get it to work and that is one barrier too high for most businesses to tolerate. Web sites which need to be used, are cross platform and mostly open.