If we're going to credit one in season play as the starter of the dynasty, it's obvious what that play would be, it's not the tuck rule play, and Drew Bledsoe likely wishes it never happened.
Not a bad (well bad for Drew's poor lung) choice and it very well could be THE catalyst, however, the discussion itself is so far flung (not a comment directed at you DI). Many things went into the dynasty and picking one moment it started is like rolling dice. Hell it could be argued that the Dynasty started when Brady's father and mother opened a bottle one of wine and put a Engelbert Humperdinck record on the turn table one evening in 1976.
If there is to be a 'dynasty started' designation then, IMHO, it would be the entirety of the 01 Patriots vs the 00 team. 2 wins to a 10 win division winner is where it begins. And even if we lose to the Raiders in the AFCDG, if we still win the SBs in 03 and 04 I think the dynasty could be argued had started in the massive turn around from 00 to 01.
Also, IMHO and arguably, we could have made it to the playoffs with Slinger Drew as QB -- not as likely but possible (we would not have won the SB, no way). Brady's numbers (if memory serves me) definitely weren't breaking any records in 01. The big differences were Bledsoe was a passer while Brady was also a leader, Bledsoe would chuck into triple coverage, Brady the kid knew when to hold 'em and knew when to fold 'em). Again
if memory serves me one other very very BFD in the 01 season was the second half of 01's D. That D became a power house and was probably playing the best football in the NFL. My memory is fuzzy on this but I only remember the Rams doing any real scoring on the D in the second half -- and even that (27 points) was far lower than the Rams' normal scoring.
Bottom line: the D + Brady not giving away points & his critical moment drives + BB&RC/CW/Other staff team preparation = a Patriot team good enough to eke out a win against anyone, anywhere. We just needed a few good bounces to string together wins and get to the big show (where the D employed the "assault and battery" tackling that made the Ram's receivers a bit, ahem, shy about some of their usually productive routes).
But if we are picking out Raider game moments, how about the AV snow globe FG that probably never got more than 15 feet high in the air?