BTC will not go up in price if it is unusable (by being unusable I mean have ridiculous fees), but while we have scaling issues so urgent like we have right now, price will be the least of our worries
Well, some people claim BTC will become a tool for billionaires only ($ billionares). Read that other thread. I think it's a ridiculous claim, because it's such a small amount of people, the rest aren't going to sit back and watch themselves kicked out and their wealth rendered useless because the fees are so big that it requires millions of dollars of fees per transaction.
I can see $100 per transaction at a very high BTC price as a sort of gold replacement, more than that and it starts becoming absurd. Something will happen before we reach such point.