Ok probably a dumb take but: doesn’t that “stable forms become more common over time” principle also apply to protons purely by principle of them being in opposition to electrons? Ie the field that coalesces into the quarks we see today because those quarks can ultimately form atoms.

EDIT: after reading the great Wikipedia article above, and a connected one [1], I think I can restate: the only place we can look for these particles is in atoms, so it shouldn’t surprise us that they come in convenient forms to support atom formation.

[1] https://en.wikipedia.org/wiki/Accidental_symmetry