I get bored with things when I can't work on them any more. I did the same thing with 1:1 scale cars. Build them.... lose interest... then start another project. That is why I work on other people's rods and customs now... instead of my own.
I built the models because I liked the creativity ....but then when work slowed down, and I started getting hungry, I would cash them out. :-) No regrets.