I think you misunderstand: 3rd party code, not 3rd party software.
Think Open Source CMSs and Javascript libraries. Anybody who's been burned by enough of that sort of thing quickly learns to avoid it. 3rd party Javascript is especially bad in this respect, generally requiring a complete rewrite before it performs the task it was advertised to perform.
I must misunderstand, yes, because I have no idea what the difference between "code" and "software" is supposed to be. Especially for something interpreted like JS. Is jQuery code or software?
Can't argue that most JS examples you'll find on the web are awful, though, or that open source CMSs are typically useless. Or closed source CMSs for that matter.
Think Open Source CMSs and Javascript libraries. Anybody who's been burned by enough of that sort of thing quickly learns to avoid it. 3rd party Javascript is especially bad in this respect, generally requiring a complete rewrite before it performs the task it was advertised to perform.