I think the barrier of entry isn't training, it's trust. McDonalds corporate signed a contract with Taylor with the caveat that only Taylor maintain the machines because they trust Taylor to do it correctly and, because the contract with McDonald's is probably enormous, Taylor has a lot of incentive to make sure nobody gets listeria from McDonalds.

It's "artificially restricted" in the same way that I could give anyone a key to my house (duplication is trivial) very easily but I don't.