I'd guess a lack of hands. Maintenance is the expensive and boring part of a distro. And seriously, why should an unpaid volunteer help to maintain a stable fou

I'd guess a lack of hands. Maintenance is the expensive and boring part of a distro. And seriously, why should an unpaid volunteer help to maintain a stable foundation for all the companies that rely on, e.g., Ubuntu 18.04? I wonder if one could create a business out of supporting such distributions against a comparatively small fee.