Business models like NiceHash (putting aside their security issues) have elevated the price of bitcoin by letting miners mine the most profitable currency and then immediately selling it for BTC. This moves the demand off the best alt currencies onto BTC; so the more block chains the merrier as long as this kinds of business model persists, and i think it will.

Also; "People have this bizarre idea that cryptocurrency tokens are ‘rare’." the belief in value is basically the foundation of all currency, why would cryptocurrency be any different?

Creating new coins is also the easiest way to introduce new features and ideas. We’re overvaluing version 1.0 because it has the biggest install base.

Decentralized ones are rare. There are lots of centralized blockchains. The centralized ones, with their cheerleaders of pump and dump get rich quick schemes, are constantly trying to convince the unaware that they have the same security model as the decentralized ones. They don't.