The so-called evangelical universalist system demands that man be immortal; he must exist in hell until he repents and then is immortal in heaven.So, as you said “nowhere is it written that God declares man to be immortal”, so why then are you arguing for this infinite chance for man to repent? It seems God demands repentance ‘now’. He puts a limit on waiting, and a limit on mans pre-mortem, post-mortem, unrepentant, unbelieving existence, with plenty of scripture to back this up.
As for .999=1 that is only because we rig the game - infinitely small numbers do not exist in our finite understanding because we can not tell the difference even though there is one. And the whole math thing has absolutely no usefulness as a proof of universalism.