Until you have an app that's not compatible with systemd. Or requires a kernel feature that doesn't work as advertised anymore. Or has a driver that requires a specific kernel version. Or, or, or...
Oh, your app was compiled against GCC 3.x? Oh, I'm sorry, it won't run unless you rebuild your software from source on the new compiler or support two runtimes.
Oh, the application doesn't support the latest OpenSSL? No problem, I'll just tweak this and add that and oh, wait, I've now spent three developer months maintaining this application that will still only run on THIS instance of GNU/Linux so we need to build a custom image and...
BUT before you even got here you need developers that know what GCC and OpenSSL are and how to maintain the kernel with the correct patches. No problem, I'll just find some senior C++/Linux fellows around... There's lots of those and they should be pretty cheap to come by...
NO FREE LUNCHES
Biting the hand that feeds IT
