It would have reeked of hypocrisy, and wouldn't have accomplished anything.
Sort of like how Trump said the election was rigged all campaign and then said we should accept the results moments after winning. Or kind of how Trump said the electoral college is terrible when Obama won but now thinks it's the greatest thing ever.
Trump said right after the election he still prefers the popular vote. His line of reasoning has been that he did in fact win the popular vote if you subtract "illegal" voting, not that the electoral college is great.
