Preface: I'm not intending to come off as bragging, but providing some justification
I make plenty enough to retire by 45. Does that mean I'll stop working by 45? No, that sounds ridiculously boring. I'd rather work part time or do contract work until I'm physically and mentally unable because otherwise I'll become a vegetable. I enjoy my work and at the moment have no intentions of stopping at any point
What I do for work is also my hobby outside of work! I enjoy work due to the new challenges that come and require solving. If I'm working on my own stuff I end up side-tracked and never actually finish things which gets demoralizing quickly. Work helps keep me on task so I can actually get to have the satisfaction of a job well done