I don't see why this calls for a new system. If anything these environments are a stronger case for a quality ecosystem where a whole community cares about keeping it coherent and up-to-date.

A minimal Debian installation for single-purpose server isn't a new idea, or I often reach for Alpine and trim it down to a dozen or so packages. These are both quality ecosystems with track records and reputations. I can get a minimal attack surface and still count on timely updates, security patches, good integration (when it turns out that I needed a dual-purpose server box and not a single-purpose box), etc. These systems scale up and down.

What I'm reluctant to trust in a deploy-and-forget system is a fly-by-night package from someone who picked a packaging system because it looked easy and didn't make them think about an actual lifecycle. A few months or years down the road I expect most of those will be unmaintained. One of the most valuable parts of an ecosystem like Debian is that they make everybody think about all those issues and actually do the work.