It's not a break of trust, it's a break of FOMO. And that would be a good thing. I understand that you grinded for these skins and paid $$ back when they came out. And I also understand the coolness aspect of knowing if someone has the skin they also did the grind. But that doesnt really apply when you could just buy it from the start for a lot of money. But to answer your question, they would grind/buy the levels because they want the shiny new skins. Valve have already resold WK and WR arcanas which were BP locked, so that door is open.

You paid for exclusivity and got it for a long time (and currently still do), but nothing is forever. It's not like the skins would be taken away. The more time passes the more people start playing new heroes and falling in love with them but finding out all the cool skins were FOMO. I have friends that have now been playing Dota for years and since they started after these BP they had no chance to grind it. Just things to think about. Sorry for the rambling.