Maybe California is a bad example. What I'm getting at is the selection for what you need is usually larger and more applicable to the conditions locally.
I see plenty of tourists with winter gear that is either insufficient, or completely over the top. Whereas if you buy locally you'd generally find the right stuff.
I think the bigger problem is that many of the tourists don't normally spend time outside, so they are used to only having enough gear for a heated building or car, even at home.