It's common for databases.

This is Percona's business model. They employ core pg/mysql developers and you can buy a support package from them. Same for enterprisedb. Pretty reasonably priced packages (like maybe $10k-ish/core IIRC) get you 24x7 support. I've only had to escalate issues once but inside 10 hours we got a pg core committer to debug some very strange vacuum behavior.