The short answer is that I can build (or learn to build) a skoolie that I would never be able to afford to buy off the lot (even used.) For what I want right now, I haven't even really seen it factory-built at any price.
I also think that I'll end up with a better product. "Better" meaning :
-Custom. I can get what I want, with the layout I want, and the features I want.
-Safer. The pictures are out there - a lot of motorhomes aren't very strong structurally, and pancake in an accident.
-More fixable. I'd like to say "better built" - but. . .Well, if I do it wrong the first time, I'll know what NOT to do the second time. I'm not trying to re-engineer something someone else built.
-Longevity. I'd rather build on a chassis with an engine and transmission designed for heavy use, rather then a box on a stretched van chassis with an engine burried somewhere under the floor. There's nothing wrong with a van chassis, but I feel like a lot of them are overloaded for motorhome duty.
-Renting an apartment around here would be about $1,000/month. $12,000 will easily get me into a livable skoolie. Double that to get it to where I'd really want it. I'd call that pretty good - after 2 years, rather then renting, I've got something that I actually own.
I have considered a Wanderlodge - they're one of the few built RVs that I'd consider - but one in half decent shape will still run about $15-20,000 to buy - and that's knowing that it will need other mechanical things, paint, etc. down the road. Not a bad deal, but again - if I'm going to take on a project like that, I'd rather start with my own blank canvas.