I'm not talking some far-in-the-future hypothesis. I'm talking about the fact that Monero's blockchain is exploding in size with negligible amount of transactions it now process.
This premise is false. You are ignorant of the fact that Monero transactions are not "negligible." You likely assume they are because: 1. Most of the shitcoins, by contrast, have negligible transctions; and 2) Monero is relatively new. In fact Monero has gained nearly unprecedented adoption and usage for an altcoin (e.g. see post #1 on this thread), although at present most of that usage is speculation. That's still usage though.
The blockchain is growing at 6 MB per day with about 3% as many transactions as Bitcoin. There is a small constant factor difference in size between the two, roughly 5x.
Upcoming changes will likely alter this factor but in offsetting directions, so I expect this to remain fairly close.
There's no PHD needed to see that with anything close to BTC amount of transactions it would making running the full Monero node unsustainable for most users.
This is also false. Moore's law will likely make running a full node (even at close to Bitcoin volumes which no one expects) less expensive in the future, not more expensive.
There's many things I like in Monero, but if something looks unrepairable without dreaded hard fork, why not take the best from Monero and move it to a new currency which doesn't have the super-fat blockchain problem?
Hard forks are not themselves dreaded. Some development processes have become so politicized and dysfunctional as to make changing anything nearly impossible, and likewise some incompetent developers have done hard forks poorly. Both of those are what should be dreaded, and both of those will be avoided by Monero.
If hard forks are needed to make significant improvements to Monero they will be done (correctly).