Re: At least Trump has finally conceded
Which has very little to do with actually conceding, and he didn't even do that. Trump stated there would be an orderly handover "to the next administration" while leaving whose administration that would be up in the air.
Being present at the inauguration of your successor is merely the polite thing to do, it has no bearing on the actual process. Biden's win has been certified by the combined meeting of the House and Senate, with Pence presiding, and that's what matters.