The difference with llvm is that nobody is selling a hosted llvm as a service, nobody is making money off llvm without contributing back (directly, I know a bunch of companies use llvm to make a product that makes money).

Redis clearly thinks that using the BSD licence was a mistake. I agree with you, using BSD attracted more people/companies to use it than if they had chosen AGPL, that's the trade-off you make when choosing a copyleft licence.

I think I agree with you on a lot of this, let me know if this is a fair summary of your argument:

Permissive and copyleft licences both have advantages and disadvantages, if a project chooses a permissive licence then that's their choice, and if they later decide to re-license then the project will probably get forked and carry on under the original licence, so as a user you can just switch to the fork and the only thing that will is the name of the package you install.

That seems pretty reasonable to me, let me know if I made any mistakes summarising your point.

The caveat I would add to that is that the project shouldn't complain about freeloaders if they choose a licence that explicitly allows freeloading. They chose a permissive licence for its advantages but they won't accept the consequences that come with that decision.