When the pros no longer outweigh the cons.

I work in a field that offers full tuition reimbursement commonly, so money isn't a barrier. No con there.

I don't have kids, so that greatly alleviates time capacity. So some con there but not as much as a parent of young kid(s) would face.

I have progressed far enough in my career and am on a path where another degree won't really help me reach my career goals, so no significant pro there.

Personal curiosity and ego do motivate me slightly. Even if I never use it at work, I would be keen to have work pay for another degree that I have personal interest in. I also like having advanced degrees solely for the accomplishment. So minor pros there.

In summary, not too late for me but easy to see that's not the case for everyone else.