open source most likely becomes a liability under CRA
It's not so much as open source becomes a liability, but rather "well known", whether open or not, becomes a liability. If you pull a random json library from github that does not even appear on any vulnerability database then you will probably be fine.
You can after-all, file CVEs anonymously. It takes no effort to stand up a fake "research firm", or two, or three doing so.
Bonus points if the CVEs are against all the shitty cybersec scan tools.
Of course there are shitty CNAs that don't care. But honestly CVEs are a useful tool for communication, people (both security people and non-security people) should stop obsessing over them.
which still leaves you with the risk of breaking stuff on upgrade, because now your product is basically baby debian sid, because you must pull newest versions all the time, and cannot stay on a stable version (that will not get patches)
e.g. if vendor drops copy of public domain libtom into its git, changes it up a bit — is that still a separate dependency? what if vendor goes "hey, siri, copilot gpt4, write me tls handshake implementation" and uses whatever is the resulting garbage, is that ok?