I had the same thought before, back when Hardware Tycoon's developer, Haxor, stopped working on the project. I was upset at first, but now I understand. Life happens. When you get to my age, you have work and other responsibilities. Most people who make these kinds of games start when they're teenagers.
I still work on the project on weekends, but that's just not enough time to finish something of this scale. I wouldn't call it quitting, though; it's more of a hiatus. If I manage to finish version 0.3 and it does well on Steam, I plan to pitch it to some publishers and hopefully hire people to help me complete it.
You're right, though. At some point, if my attempts to revive the project don't work out, I'll move on. But it hasn't come to that yet.
Right now, I'm trying to clean up the current version, v0.2.0, and open-source it. Unfortunately, it's taking some time.