Lots of third party software hooks the kernel for various things, such as drivers for enterprise RAID or proprietary networking, and whatever it is Nvidia does

Lots of third party software hooks the kernel for various things, such as drivers for enterprise RAID or proprietary networking, and whatever it is Nvidia does these days. Those go far beyond the user space interface and are dependent on binaries staying unchanged. This is for them. If you are running user space applications only on upstream supported hardware, there is no reason to stay with long time supported kernels, just follow the regular stable which is much easier for everyone.