They did provide security updates for several years longer than any competitor. Even (or especially depending on your point of view) for a company like Microsoft a user shouldn’t expect updates indefinitely at least not for the normal retail price.
And to be clear: I also don’t want to blame any of the named Linux distros. I recently migrated an old CentOS 6 server and it was about time. Sure there were still some security updates but several software components hadn’t received updates for years and there were a lot of workarounds necessary to keep the thing in a somewhat decent and modern state.