You sound like MacGyver. I hope you're not saying we could all get our standing rigging replaced for something like $40 and the fact that you did it once, you don't mean to say: you'll be able to duplicate the bargain the next time you need it replaced. Which maybe sooner than normal.
You not only called Tager delusional, you managed to slip in a bust on his rigging job!
Anyway the OP is pretty vague. Obviously a gift of a boat or free use of a boat would be cheaper than anything, initially. And hey, if you can do it once you might be able to do it again.
However, using the all things being equal approach to logic tells me a low end rental would be cheaper than a sinking boat. It May not be cheaper than a gifted boat, but then that would not be all things equal, would it?
Let's see: if the stove goes out, its the same. If the refer goes out, the same, the toilet same, Paying the utilities, same. Replacing the $40 rig, the $50 diesel, the thruhulls, the nav. lights, the any other boat part or system, Not the same! An apartment doesn't have them. As for the roof, that's the landlord's.
You can take any logical shortcut you want to justify the economics of a live-aboard, but it's just self delusion. Why encourage it?
Your all things equal argument is fine, but you are using faulty assumptions as a premise. Ceteris Paribus, with all things equal everyone has the ability to get online and ask for help when they need it, with all things being equal anyone can learn to do rigging themselves and borrow tools from each other to get the job done, all things being equal learning to do things yourself can be an effective survival strategy, we don't always have to pay people to do things for us just because there are people there to pay, etc. If everything in the world were market driven no woman could ever get her mom to watch the kids on a Saturday night ...
Joshua Slocum didn't need no damn help fixing his rigging ...