the key is "A Good Survey" But finding one is the hard part. Mine cost me $1800 and it had a nicely written report in a binder but mentioned nothing of the holes in the holding tank. The obvious rotted fitting going into the tank. Or the Frozen windlass. The radar that would not function or the dri-rot I found behind the fridge or the leaking windows and I could go on and on. No question about it, but a good handy person wirth some basic knowledge on how things work could do just as well on their own.
I can appreciate your comments about surveyors. Some are good, some are not. The vast majority of us can do most of the survey ourselves, takes little skill. Writing up the specs, numbers, equipment on board, taking pretty pictures and putting together a presentation. Also, we can easily verify most of what's working or not, correct speeds, engine performance, electronics, windlass, head, galley, etc., etc.
What we can miss it the little things that could be big things. Like a weak hull that can only be detected with instruments, or a wiring flaw, or something installed wrong or missing. Leaks, broken things, old wiring, hoses, cracks, etc. Things that we are unfamiliar with and he's seen a hundred times. And that's what you pay a surveyor for.
However, you can easily get buy just hiring a good mechanic that knows this stuff, and perhaps an electrician or a few other experts.
I've done all of the above, and for the most part my surveys were not a real bargain. The mechanics were.
In some cases the deal is so good, and there's buyers standing behind you that you just buy it as is. I've done that a few times and always made out handsomely. Sometimes the deal is made only if timely... like within hours, not days.
I missed one good deal for waiting a few hours. Sold for $96 and I was in at $95, boat worth north of $160. There were no surveyors, but could get a quick look see. Damn!
Overall, a survey is not a bad thing, and if one is very conservative and wants nothing uncovered, they'll get a survey, have a mechanic and electrician check things out, too.