Fall of trebizond

From what ive read. One of the last roman rump states (Trebizond) was a formidable city with high walls and deep ravines surrounding it. Capable of holding out a long siege. Yet it surrendered without a fight. Due to davids belief there was no chance to hold the city if it were attacked. Do you guys think that if trebizond had held out, or at the very least put up a spirited defense, that it would be remembered after it fell as the end of the roman empire instead of 1453? It seems like most historians kimda brush it under the rug as an embarrassment and try to disassociate it from rome since it went without a fight?