You can bet on it because everything is bounded, barring some additional fork: if blocks are as full as they can be from now till eternity, the growth of the chain will be far less than the growth of relevant technology that supports chain growth (hard drive tech, in this case, but also processor power and bandwidth.)

I mean, I am seriously good for several more years on the piece of shit Raspberry Pi that I bought several years ago for negligible money. You can run a high-performance node in the form factor of a deck of playing cards. And that's without using a single scaling optimization, that's a full node with the entire chain history. The present resilience is testament to the vision of the Core devs for these last years that decentralization has been prioritized so hard.

This sounds at this point like I'm nitpicking, but I'm just saying, there are legit philosophical and design tradeoffs to be made here, so we don't need to water down the argument with non-issues.