Mining like hell doesn't drive the price up, all it does is drive the difficulty up where everyone is losing money, and this is of course unsustainable.

People need to want to buy and hold the coin in order to drive the price up. Even just driving it up enough where increased mining becomes sustainable.

That likely happened with Litecoin because of people did not like how things were going with Bitcoin and ASICs and centralization, and possibly other things people didn't/don't like about Bitcoin. Maybe how it has started to become corporate, BCF antics, hacks and scams and bad PR, etc.?

Monero (and to be fair Darkcoin, even if I think it is inferior) has gained the following it has because people do not like how things are going with Bitcoin in terms of privacy and fungibility. There has been too much talk about blacklisting/whitelisting, too many papers showing successful blockchain analysis, reports about Coinbase banning people because they send Bitcoins to a poker site, etc.