Unfortunately a lot of companies don't really seem to realise that when they include 3rd party JS they're implicitly trusting the security of that third party. I'd imagine many don't do much in the way of due diligence before including the scripts.
As mentioned in Scott's related blog post (https://scotthelme.co.uk/protect-site-from-cyrptojacking-csp...) SRI is a decent at least partial defence against this kind of thing, but unfortunately it hasn't (in my experience) seem much in the way of takeup as yet.
"Same attack as described here: https://labs.detectify.com/2017/07/13/a-deep-dive-into-aws-s... … it's scripts hosted in a S3-bucket without proper access controls"
Edit. Also see https://scotthelme.co.uk/protect-site-from-cyrptojacking-csp...