If you wanted to upend Core, then you should have more competent people who would have advised you that unbounded block size doesn't have an equilibrium.
If you have successfully demonstrated that unbounded block size cannot reach an equilibrium
outside a majority-collusion environment, I have missed it. If your argument is that there is no equilibrium
in a majority-collusion environment, then your fear is as valid for today's Bitcoin than it is under unbounded blocksize. Nakamoto consensus is -- as far as we know -- dependent upon 'a majority of honest [miners]'.
And as a practical matter, Bitcoin operated just fine for multiple halvings with no practical bound on blocksize. This may be partially explained by a relatively amount of mining centralization, but such does not seem monotonically increasing. Certainly, we've had actually naked over half hashpower in a single entity before.