Good points. GSP mostly got by on attributes too though. He had skill, but from the first time out of the gate we saw he had that something special that made him make guys like Mayhem look like they were white belts.
Also, we can't compare Covington to Fitch. Colby's boxing, while not great, was leagues better than Fitch and there was also the added factor of there being a lot of emotion in that fight. In fact, we can reasonably say that all MMA boxing is better these days than it was for most of GSP's prime. One of the things that made GSP so impressive was that he trained with elite wrestlers, BJJers, boxers and Muay Thai fighters when a lot of fighters might have one of those, but not all of them. These days that's no longer the case. More money in the sport means more expensive camps and you'd be hard pressed to find a contender who's not getting in rounds with top level guys from all the disciplines or getting top level training. COVID-19 of course complicates things and who knows what the training is looking like. I don't think you can say much about most of the fights happening right now and their long term implications for people's careers. I guarantee you if GSP had been scheduled to fight Nick Diaz (a dangerous BJJer with very good boxing like Durinho) and had the fight canceled with a 6 day replacement of Robbie Lawler (a hard hitting all rounder scrapper), he would have fought the same type of fight, smart and technical.
I do agree with you that Usman eats more shots than he should and it makes me believe he's going to get floored one day, but the guy has won 12 straight so he deserves some props. GSP is still safely the GOAT and it's good to be protective of them, but there once was a time when all people did on forums was trash him for being scared, safe and boring and it never made sense.