That's how one might hope it works, but it doesn't. First of all, it's a lot to expect of anyone who's been struggling in a field for well over a decade (from the start of grad school to the grant of tenure) to suddenly turn around and stop doing the things (like chasing novelty at the expense of rigor) that have been key to academic survival up to that point. Second, the system doesn't incentivize that kind of behavior. If you put your grant pipeline at risk by making a big bet, you could well end up spending most of your time teaching undergraduates because academics who don't pull down lots of grant money are penalized with heavier teaching loads. (Not that this ought to be seen as a penalty, but that's another rant.)

The pressures applied to getting tenure are the same pressures that get applied to keeping your lab funded, getting your graduates and postdocs jobs, etc.