You talk about the other teams being "well off the pace of the McLarens". The only year that was really the case was in 1988. In 1989 the playing field levelled out a bit. Also, remember that in 1990 Prost went to Ferrari who had a decent line-up with him and Mansell and probably a superior car to the McLaren, as the Ferrari was reliable and had the advantage of semi-automatic transmission. However, Senna still managed to win the title that year, and the following year, when the Williams was the car to be in. It had probably a better engine and they had Adrian Newey as the chief aerodynamicist then. Also, who could forget 1993, when Prost came back with the Williams, which had top of the line Renault engines, traction control, active suspension etc- it was one of the most technologically advanced cars ever seen. However, Senna still managed to make Prost look ordinary on more than one occasion in a McLaren that was using second-string Ford engines. And who could forget the Donington Grand Prix that year, when Senna went from 5th to 1st on the first lap and stayed there, lapping the entire field on his way to one of the greatest victories ever seen.
There is a reason Bennetton didn't win races when Schumacher left- he took his race director Ross Brawn (a master tactician) with him to Ferrari. Also, this is the reason the allegations of cheating stopped at Bennetton and started at Ferrari- Schumacher. He has this "win whatever the cost" mentality, even if it means running illegal cars, team orders (when they were outlawed) or, at it's basest form, running his championship rival off the track (Hill 1994, Villeneuve 1997). He's the Bulldogs of Formula 1 pretty much. It is for these reasons and the ones I mentioned in my previous post that for most people, Schumacher can never be mentioned as the greatest, or at the very least above names like Senna, Fangio, Clark and Prost.
BTW Ferrari hadn't been no-hopers for ages when Schumacher arrived there. They had a good car in the late '80s but the McLaren's were better, however the team were good enough to vouch for the 1990 title with Prost. Their problems after that were managerial- again that changed when Schumacher brought his crew with him.