The past 30 years of the Linux kernel's evolution has proven that there is no need for a stable kernel ABI. That would make refactoring, adding new features and porting to new platforms exceedingly difficult. Pretty much all of the proprietary kernel modules have either become open source or been replaced by open source replacements. The Linux community doesn't need closed source kernel modules for VMWare anymore, and even Nvidia has finally given up on their closed source GPU drivers. Proprietary Linux kernel modules have no place in the modern world.