hiring someone to solve your problem is mostly not a guarantee they'll actually solve your problem. it's just that they'll invest time to try to solve your problem. there's a reason you'll probably don't want to outsource a critical task to the cheapest elbonian bidder but hire someone more expensive with a good reputation, experience in the field and maybe even developers with fancy degrees.

you are free to sue any vendor, but it'll only work if they fail to honor the contract because of gross incompetence and wrong advertising.

i could hire a hoard of self-taught stackoverflow-copypasting programmers for 10$ an hour to create a novel unbreakable crypto algorithm - i would get lots of stuff, except secure crypto.

i don't generally disagree with you. otoh 15 years ago i've been assigned coding and sysadmin tasks by my clueless PM that were so way out of my league i didn't even realize they were way out of my league. my situation was pretty much exactly in the same as the bad guys in OPs post - i asked for the 3rd party sysadmins help because i wouldn't even know where to start (my boss back then also sold the customer superhuman AI, though this time i was knowledgeable enough to refuse the task outright - he was very disappointed in me and accused me of not having the right get-things-done attitude).

i've learned a ton in the meantime, but another, more recent personal story in a more expensive company: a coworker of mine worked on a problem for several weeks before he gave up. this isn't possible on the available hardware, he said at 6pm and i thought about it and stayed at the office until 4am and solved it (that really happened and i'm still proud of it). but hire a different company, be it cheaper or more expensive, and they might have solved it in 15 minutes by knowing the right pre-existing library to use - or, if you're unlucky - also failed and declared it impossible after investing 4 man-months.

you're not an expert in most cases and probably unable to identify a problem as trivial or impossibly complex - and neither are the judges. i always have to think of the story about the earth moving companies that quote impossible prices and then always encounter unforeseen problems to get profitable. i mean, in a free market economy everything sorts out itself, doesn't it? the incompetent company looses all credibility?