It's a tad more complex than that though.
When the Jag-Stang came out it was a rather maligned mid-priced instrument, particularly the bridge and the pickups. So the majority out there were probably already modified, esp the 1995-2001 "first run" guitars. People usually copied Cobain/Bailey and put a TOM and at least a SD JB in the bridge to copy their idol. I've seen a few even put EMGs in theirs like mine surprisingly (which were in it when I got it).
And unlike a strat, aside from necks, there's not a lot of easily accessable, high profile, choice for aftermarket bodies. There's just Warmoth that I'm aware of and theirs is a contoured swimming pool route very unlike the original, if unfinished, slab body the Fender OEM guitars had. It's not like a Stratocaster where everyone and their sister has some version of it. And "underground" makers require some social networking to find.
Building your own body...especially the Jag-Stang, can be quite challenging, especially if you're new to wood working. For starters, you'd need either to buy the blueprints or get someone with a Jag-Stang to trace their body for you. Then after cutting out the shape, there's finding the centerline so the neck, pickups, bridge....all the hardware, line up correctly, which the asymmetry can really throw you off, it even did to Fender Japan (my 95 and the Fiesta Red one from the 1996 sweepstakes had the same problem of the neck being slightly angled to the right bringing the strings out of line, I shimmed my 95 to fix that). Then there's tools...at the lowest you'll need a pull saw to rough it out and a scroll saw and a lot of patience to cut the body out...plus a drill and a router to cut the cavities out for the electronics and possibly the bridge. Not every one has the time/skill/budget/workspace to do that.
Some people find it easier just to start with a barebones "chassis" and work up from there. That's also why I wish Fender would just release the Jag-Stang as a lower-mid-priced Squier and be done with it. Then there would be a good source of quality Jag-Stangs out there to modify without ruining original stock. They had that Hollywood prototype in 2016, that's what I was hoping for.