[RustyRussell]

Your figures are about right, but 70 years is a long time to assume nothing else changes.

As to "it's not even bitcoin" you're flat wrong. Holding a valid Bitcoin transaction is definitely Bitcoin, and with Lightning you always do. This is why it can't be done without bitcoin.

And from a FOSS development perspective, bitcoin is the only project in the *cryptos" space I consider serious. I wouldn't base a project of mine on any of the other chains, and I think I've earned my graybeard enough in FOSS to make that judgement.

[Disclaimer, I work on Lightning standards and one implementation, since 2015]