Not true. And as I pointed out, the NFLN broadcast of Titans-Colts last night did that exact thing: They compared the first 9 weeks of this year to the first 9 weeks of last year.
Well gee, let's see... Belichick was in Cleveland 5 years. According to you, we should take the 5 year period before he arrived as the comparison set? After all, using data sets of different sizes is "absurd", right?
Cleveland in the 5 years before Belichick arrived: 44-34-1, 3 CCG appearances
Cleveland in the 5 years Belichick was there: 36-44, 1 playoff victory
Looks like the team Belichick inherited wasn't all that bad, were they? BTW, the Patriots are 3-5 in the first 8 games of 2020 compared to 8-0 in the first 8 games of 2019.
You really need to add the context of what happened in cleveland to your "analysis", if just looking at records can be considered an analysis... Shottenheimer put together the winning teams in cleveland... when he couldnt get over the hump, Modell fired him, replacing him with Bud Carson, who did well with Schottemheimers team for a season, and then ran them into the ground, going 3-13 before getting fired half way thru the season...
When Belichick came into Celveland, he reworked the roster to his liking... granted the turn around was not as great/dramatic as what he did in New England, but he didnt have Brady... Then the world caved in when Modell announced the move to Baltimore in 1995... A Football Life had a great episode about it...
What your point in this whole argument? That it was all Brady? Ok, maybe it was... but that also negates the great defensive efforts made by the first three super bowl championship teams... But regardless, you need a greater sample size of Post-Brady Belichick to see how the whole story will turn out...
The two, Brady and Belichick, are in two completely different situations... Obviously Brady was a significant reason for the success in New England... It cannot be denied... 2008 is the perfect illustration of that... and no i dont mean the record... But the overall offensive production of the team dropped significantly, dropping from a 315 point differential to a 101 point differential...
Been saying this for a while... This argument isn't going to be answered in the first half of the season, or even this year...
and for me, the successes in New England are the direst result of both of them