I have and would again pay for a bike fitting, as a service and as a source of information. One does need to pay for information. By now I'm learning pretty well what contact points work for me, and how to adjust to discomforts, so it's been part of a learning experience.
But to try on a jacket? No way! If I find a bike jacket that fits, that I like, and that fits the purpose, I buy it there. Who knows where I'll find the right item if I wait? But if I don't buy it it's not because I can save $5 online, it's because it was not suitable in some way.
If I have to deal with some sort of browsing pressure while in a store, even a bike shop, it ceases to be a pleasant experience, and I spend my time and $$ elsewhere.