Officially we are not guaranteeing any
specific future development on legacy licenses (which is why the warning exists), so
@Richard G is correct to say don't assume anything past what is functional now (CentOS 9, Debian 12 / Ubuntu 22).
@zEitEr is correct that going with a CentOS fork like AlmaLinux takes you to 2032 -- a little more than 7 years away.
Even if it ends there, that means these legacy products would have had an approximate
30-year run -- something virtually unheard of in the software world. We understand any disappointment, but we ask you to remember: no one else would have delivered this much value -- no one.
What our customers received goes far beyond what is typical for software, and we're proud of that.