Linux LTS releases are not particularly stable from the perspective of someone who wants to distribute applications as binaries. Its API can change with every release, i.e. every two years. It's incredibly unlikely that a binary compiled for Ubuntu 18.04 will be able to run on Ubuntu 20.04 (as in Python etc.).
To contrast, if you take a Win32 game from 2003 that targets DirectX 9, it probably runs fine on the latest Windows releases. (You might have to enable some compatibility mode.)
"BUT BUT BUT if it's packaged with the distro it's no problem." Remember we're talking about proprietary applications (mostly games) here. Having these packaged with distros for years after the devs moved on to the next project is just a pipe dream.
My original statement was that if this is really a problem for you then you need to stop writing and distributing proprietary binaries and open source your game.
I know this is a hard pill for game developers to swallow but there is no other way. Open source communities move fast, they are not going to slow down just to support some opaque binary blob that is illegal to redistribute or fix bugs in, and that the original developer doesn't even care about anyway. It is nonsensical to expect these communities to work exactly like Windows. These are not fortune 500 companies with billions in the bank like Microsoft that can afford to keep innovating while also supporting every single legacy program in existence forever. The only way open source communities can provide the same level of support is if you provide source code that other interested parties can keep up-to-date without worry of being sued.
Expecting every distro to have the exact same release & support cycle is nonsensical.