Given the consistent outages everywhere on GitHub, they actually should put GitHub Actions under a paid tier only if they want their platform to be sustainable and stable. Period.
It's quite irresponsible of them to have almost all the core features free and a paid tier would significantly reduce abuse of it (and especially GitHub Actions) like this.
If they don't, then don't be surprised to see more outages on their platform.
Do you realize how disastrous it would be for the open-source ecosystem to remove actions from the free tier?