On SaaS/mobile apps you have often daily new versions of software coming out. That's what users/developers want. They do not want 3 year+ stale versions of their software being 'supported' by a third party distro. I put supported in comments as it only really applies to security and what not; not terrible bugs in the software that are fixed in later versions.
Even on servers where it arguably makes more sense it has been entirely supplanted by Docker which ships the _entire OS_ more or less as the 'app'. And even more damingly, most/nearly all people will use a 3rd party Docker repo to manage the docker 'core' software updates itself.
And the reason noone uses the six monthly releases is because the upgrade process is too painful and regresses too much. But - even if it was 100% bulletproof, noone wants to be running 6-12 month out of date software on that either. Chrom(ium) is updated monthly and has a lot of important new features in it. You don't really want to be running 6-9 months out of date on that.