This is a great point, some of the lightly used bass boats I've seen for sale at the shop make me thankful for the one that I bought from a co-worker for $5,000. $12,000 for a redo that complete seems like a pretty good deal to me.
The one thing I'd really like to have done is a complete re-wire on mine. There are so many little electrical gremlins from 25 years of different people fucking around with things - the front graph loses power every time I start the motor, if I hit a big swell going too fast I get a short alarm and the engine stalls for an instant, one of the live well pumps only works part of the time, etc. I always figured that a rewire was a huge ordeal that any shop would charge at least $2,500 for.
But the motor is still really strong and hasn't lost much (if any) compression according to the mechanic. I put a new lower unit on it last year and it's even happier after that. As long as I feel good about the motor, I guess it wouldn't be a terrible strategy to put some money in to this one instead of spending $50k+ on something like this:
https://dallas.craigslist.org/mdf/boa/d/colleyville-2017-ranger-z521c/7288491301.html