Question for people who actually know anything at all about transitioning: what happens if a neovagina falls apart? Is it actually a wound, or is just an odd stinky skin pocket? If it grows hair, does it feel itchy in there? Are trans people in constant pain or does it vary?
If you mean like a neovaginal prolapse, that very rarely (if ever) happens, AFAIK. I think I've maybe seen a single picture of one before.
Rather than "fall apart", neovaginas more commonly start to heal themselves shut if the troons neglect regular dilation in the first year post-op (because yes - it's a wound). If they're good about dilating for the first year or two, then they can usually ease off since by then the neovaginal canal has given up on healing and is held together by lots of scar tissue. Someone made this comparison before, but think of it like pierced ears: if you don't wear earrings for awhile, then the piercings (especially new ones) will probably heal and close on you. Older and larger piercings are less likely to do so.
Aside from this, fistulas are an extremely common complication. Usually recto-neovaginal fistulas (see that unfortunate troon with poopy pads from a couple pages ago), but I've also seen urethro-neovaginal fistulas (reminds me of the "women pee from their vagina!" meme, except it's real for some transwomen).
Probably the closest thing you'll see to a neovagina "falling apart" is when bits of the neolabia (or even the neoclitoris) become necrotic and eventually fall off. I'm personally convinced this is usually - although not always - the fault of the troon for being unhygienic and not doing the aftercare properly. See
Jonathan Yaniv as an example of this.
Yes, MTFs will get hair growing inside their neovagina and all over their neovulva unless they get like 6 months of electrolysis treatments beforehand. Most won't bother to do this though, or they'll only do the bare minimum (like a handful of laser hair removal sessions which are NOT permanent). And yeah, it's very irritating, unpleasant, and embarrassing for them. Dilation makes it even worse since it ends up compacting gross, smelly hairballs at the far end of their neovaginal canal. Imagine having to fish hairballs out of yourself...
Many MTFs end up with some level of chronic pain (from nerves, scarring, abscesses, or whatever) and lifelong complications, yes. It's impossible to say
how many though because troons constantly lie about and sugarcoat their SRS experiences. My guess is more than half, but this is just a guess.
tl;dr Slicing up your genitals and messing with your urethra in particular is a very bad idea unless it's truly medically-necessary. You're just asking for serious trouble...
Note: I'm not a medical person, so all of this is just based on my own observations. If I got anything wrong, then please feel free to correct me!