There’s a big difference between “building things for fun and accomplishment” and taking on the intense obligations of continuing to be a CTO when a major exit is on the table.

I totally understand that there are people who relish in the challenge, feeling needed and important to their team, and the prestige and visibility, but I don’t really understand what their brains are doing and what.

OP talked about the luxury of being able to fly out the grandparents to help out taking care of the kids when things get busy at work. That doesn’t sound like freedom to me.