Yes there are people that buy. The deals are clear before launch so he can decide to buy or not the version that would miss the dlc.
The fact that it is more important to someone doesn't make the missing skin more relevant than one year game lock.
And in case of tr they were even more guilty because of the piss announcement trying to pass as permanent exclusivity while Sony make it clear that it would come first to their console.
You only make a decision to buy or not buy if you have both systems. If you only have one you just miss out. Also you are just saying missing skin but in destiny you missed out on not just skin. You miss content which included maps, skins, strikes etc. Its just not one piece of content is quite a bit.
The only thing wrong with the TR announcement was that MS should have shut down all talks about any other system until after their agreement. I am only thinking of this for the business case. MS can say the agreement is timed which is fine, but allowing talk about another system during that time frame defeats having a timed window.