> Not convinced it's the application of OO patterns that leads to bad code but bad programmers

There's one thing I would point at. When non OO code is bad you can usually point at the problem: bugs, performance, security issues, coupling, so on and so forth.

OO code can be bad yet contain no debuggable issues. Once it's laid out, noone is going to "fix it" because it's not technically broken. It'll just rot due to lack of maintenance, until there's noone left with a good mental map of it and enough of the non-OO contents are broken enough that it gets replaced all at once.