Earlier quoted context omitted.
Source-available is still hugely beneficial to users, even if it’s not open source.
Closed source can (and does, see Windows) provide source to customers too.
This just means it's Source Available to certain customers - Closed Source to others.
I agree that universally available "timebomb open source" "Source Available" is different from "Closed Source", though.
It allows for certain risk planning, like: If HashiCorp goes away, we will be able to host and patch (and keep using) product X for the foreseeable future - along with the ability to actually read the code and determine if it is something worth touching with a ten foot pole...