I think I understand what you were getting at by "there is no such thing as running out of entropy". Would you say there is such thing as "not having adequate entropy"?
Not really. A CSPRNG is either initialized properly or it isn't. Once it is, entropy has ceased to be a concern. The original LRNG design misapprehends the purpose of continuous "entropy collection", which is about post-compromise security (it's essentially a rekeying operation), and not about any kind of cryptographic exhaustion.
It's best to think of this as an OS/distro detail; if you can reasonably expect /dev/urandom to give you insecure bits, your distro has a vulnerability.
That said: today you'd just use some variant of getrandom.
> It's best to think of this as an OS/distro detail; if you can reasonably expect /dev/urandom to give you insecure bits, your distro has a vulnerability.
Isn't that more a function of hardware than software? The hardware random number generators on modern CPUs pretty much eliminate the need to worry about entropy...