It's possible much later in career when you establish yourself in a certain domain. You become valuable enough that you working half the time (or even just consulting) is more valuable than 2 other employees.

But people who can do that are also probably in positions to retire early already. Either with PhD's and 10+ years working on some now-extremely-valuable tech (think AI if you worked on it in the 2010's, or data science in the 00's) or some otherwise reputable name in their industry.