Real talk: Anybody who was within a hair's width of grabbing a record like that would be gunning for it. You don't run a marathon and then give up after 26.1 miles.
We're not talking about making the best chili in the office....or being the best at playing Mario Bros with your toes....or being the best troll on SpursTalk.
He has a chance to cement his legacy as the BEST REGULAR SEASON COACH OF ALL TIME, on top of already being the best overall coach of all time (regular season+playoffs), 5 championships, 3 COY, and now an Olympic gold.
I know people say Pop doesn't care about accolades and he tries to follow that act, but anybody with any sort of self-respect would feel the same way. You don't give up a chance to be the best at what you do at a high level.
You can call it ego or hubris or whatever...but he has a chance to achieve something that nobody in the NBA has ever accomplished. If you have that chance, you go for it.