Offensive line was average. Run game was average in 2001 and beyond terrible in 2003. Brady didn’t have top 5 stats. He was in MVP running in 2003 and 2004 and received votes. He was a top 5 QB by league consensus. People wondered what he would be like if he had the same weapons as his other elite peers, and that was answered in 2007. People wondered what he would be like without Belichick, and that was answered in 2020.
This is not quite accurate. In 2001 the entire team was pretty average including QB, but they played better as the season went on and improved. While they weren't necessarily great at running the ball, they did it to the tune of 8th most attempts in the league for the regular season and had the second most rushes in the postseason. The passing game was also an extension of the rushing attack, their yards per passing attempt was near last in the league for a reason. Screen passes were all the rage. Tom threw one TD in the entire 2001 postseason.
In 2003 the RB position was dangerously thin as Antowain Smith was on his last legs and the only big bruising RB they had. They rested his legs in the regular season by using Kevin Faulk heavily. This changed in the postseason, Smith led the entire postseason in rushing attempts. And again, the passing game was an extension of the rushing attack, Tom's yards per pass attempt were some of the lowest in the postseason.
In 2004 Corey Dillon's 1635 yards rushing was the third most in the NFL, he also ran for 12 TD's. They were one of the best rushing teams in the league.
Also nobody at this time was opining about what would happen if Tom had better weapons. The short passing game was their scheme, it was by design. Also Troy Brown, Deion Branch, David Patten, Kevin Faulk... they weren't exactly devoid of talent. In 2001 Charlie Weis had to hold Tom by the hand and prevent him from turning the ball over, either by interception or fumble... of which he had many.
Tom worked hard, he improved... this notion that he entered the league like gangbusters and led the NFL in passing and TD's is revisionist history. These were his development years, and he had the good fortune to be on a well coached team with a stout defense. He really started to come into his own as a passer in 2005 and beyond... like most rookies do.
Mac is the same player he was as a rookie, and if you're not getting better in this league then you're regressing.