When my company makes deal with such vendors, it comes with a contract for support when things go wrong. If they don't honor the contract, they lose our business.
If we rely on them so heavily that it'll affect our finances significantly, I'm sure the contract has plenty of penalties if we don't get that support.
But yes, for small one off deals, you could be screwed. And guess what - it's still your job to fix it, just as with open source. Your employer cares for the end results. They expect you to say "OK, vendor X screwed us. Here is plan B."
Absolutely. Ideally, you always have a Plan B and taking a vendor to small claims (or otherwise court) is not really a Plan B. It's not always possible to have a good Plan B. You can and should do due diligence up front but things can always go south for any number of reasons. Maybe collecting some sum of money down the road doesn't really make you whole if your business gets blown up. And you'll be long fired if the decision was on you.
If we rely on them so heavily that it'll affect our finances significantly, I'm sure the contract has plenty of penalties if we don't get that support.
But yes, for small one off deals, you could be screwed. And guess what - it's still your job to fix it, just as with open source. Your employer cares for the end results. They expect you to say "OK, vendor X screwed us. Here is plan B."