They do have the best RT in the league with Sebastian Vollmer and a solid defense. Belicheck may be 1 of the greats but saying that this will be the best coaching performance of any season in modern history hell no the pats have only played 7 games, Shula's 72 phins was the best coaching performance of all time with Walsh's 84-85 niners
I'm not old enough to remember either of those teams outside of grainy footage. And these Patriots are flat out dominant, even though there are teams that you could say have more talent on paper. Tom Brady is obviously an all time great, but at this age where he doesn't have quite the arm strength he used to, the offensive game plan is tailored to him perfectly. Or Dion Lewis, cut by the Colts who were a barren wasteland at RB, now holding the title of the best pass catching RB in the league. Why? Because Bellicheck and the coaching staff tailor the game plan to his strengths far better than any other coach could. They have a defense with some solid players but without a Von Miller or JJ Watt type superstar being game planned and coached so well that they happen to bring the right type of coverage for the right team every single time. Now I hate the Patriots with a burning passion, but I have to respect that this level of dominance with this level of talent on the team is nearly unprecedented. Didn't the Niners squad you mention have Joe Montana in his prime, arguably the greatest qb of all time? And Jerry Rice was either drafted then or the year after (I can't particularly remember). Either way, those teams were loaded.
Tl;dr - hate the Patriots, but Bellicheck and his coaching staff are having a historically great season.