Eventually I could feel my skills stagnating. Yes, I was able to do more impactful work, but keeping up with high-level industry tech changes became difficult as I was spending more time on a whiteboard than at a computer.
Or maybe they liked the 10 years job but knows they won’t be working for 10 more years.
Ideally, yes...I don't want to be working full time in 10 years. A few more ~year long gigs, and I'll likely put myself out to the 1099 pasture.