Bet that happens again in 2026 - Merc, Ferrari or McLaren (or multiple) catch up to RBR in 2025, we have a tight championship, then one team nails the rule change. If Brawn had had dedicated Honda or Merc cash in 2009, who's to say they wouldn't have hoovered up '10 and '11 with the head start? Merc nailed the turbo hybrid change. Only huge rule change I can think of in recent memory that produced a close fight was 1998's narrow-track, grooved tyre (ugh) cars.
even in 1998 McLaren had a way better car, just that it was unreliable and Schumacher would relentlessly punish mistakes
(Argentina, Canada, France, Britain, Monza spring to mind) at the start of the year, McLaren were streets ahead but I accept your points.