It's not that. It's that after he beat Damon Hill, the field did not become all that much richer in the number of WDCs and number of winners never got all that high for another decade. That is what's remarkable. There are two interpretations of that: either all other drivers were freakishly bad in that decade or that certain German was freakishly good.
The era from 1994-2001 was one of the weakest in modern history imo. There was Schumacher and then there was the rest, and its not just because Schumacher was so good. Lets look at his rivals over that period.
David Coulthard? An inexperienced david coulthard mind you. At his best he was good. Most of the time he was incompetent.
Damon Hill, a good driver but thats it, who didnt even get into F1 until his 30s.
Eddie Irvine, nothing special
Rubens nothing special
Mika, the best of the lot back then, a fast but a guy who took almost 100 gps to win a single race.
Berger, good but a number 2 as proven by his time next to senna.
Alesi, no better than berger.
Frentzen, weak and fragile.
Herbert, and other assorted Schumacher team mates ect ect.
And thats about it. None of these drivers stood out as super stars compared to anyone, let alone Schumacher. If you removed Schumacher which drivers would have stood out among the ones I listed? None right?
It was just a weak era because the natural course had been disrupted by Senna's death. He should have kept Michael honest for another few years. Because of this disruption in the natural order, Michael lucked in and was able to profit from beating up on so many meagre talents (compared to his) and his record reflects that.
He is very lucky that he raced the majority of his career without a truely great rival, like Alonso, who immediately ended Michaels domination the moment he got his hands on quality machinery. If Lewis or Alonso would have been around from 94, Michaels record would only be 50% of what it is.
Was there ever another time in history when someone of Michaels talents never had a comparable rival for so long?