I think the explanation is wrong: wikipedia offers a completely different explanation https://en.wikipedia.org/wiki/Tidal_locking.

Planets can become tidally locked to the sun- mercury is. Probably the timescale required for the other planets is just much longer

EDIT: Apparently mercury isn't actually tidally locked to the sun, TIL

I don't see how my ELI5 disagrees with the wikipedia article.

	▲	anlsh a day ago \| parent [-]
		wikipedia's explanation works for uniform bodies, yours doesn't. And since tidal bulges seem to be symmetric, there's no away to explain away the deformation as making one side heavier