Actually, this is exactly what I was trying to say. You don't have to stop buying plat completely. Just choose what you spend plat on wisely. Each time you spend your plat it is a vote. So if you would like to see more vanities, then buy more vanities. I can assure you if people start spending lots of plat on vanities then STS will add more. On the other hand, if nobody buys vanities, they will probably not make more.
Same goes for the crates. If nobody buys them, then they will probably phase them out.