In fact, this is what most "professional" philosophers do. The theories they prefer are more or less set in stone by the time they do their Master's (age 22-24)

In fact, this is what most "professional" philosophers do. The theories they prefer are more or less set in stone by the time they do their Master's (age 22-24). After that, it's mostly refinement and minor adjustments, and arguing with everyone who disagrees. Of course, those minor adjustments make all the the difference between a convincing theory and a ridiculous theory. Some people are exceptions; that's when you hear them being referred to as "the early Tycho", "the late Tycho", etc.