[prohobo]

My guess: from a speculative standpoint Bitcoin is finite and the only real competitor to fiat. There's also a large amount of sustained hype. It's unlikely to flatline unless something really major happens.

Blockchains like Ethereum are not (and aren't meant to be) alternatives to fiat. In fact, the best thing for ETH would be low price, since it's mostly used as gas. Altcoins are almost entirely vaporware until ETH tech matures and consumer services become feasible. Until then, any high valuation of either ETH or Altcoin is 100% Tulip Mania. I have no idea about any blockchains outside of Bitcoin or Ethereum.