For your average developer who just wants to get something running on a port, Kubernetes introduces two barriers: containerization and Kubernetes itself. These are non-trivial things to learn, especially if you don't have an ops background, and both of them add substantial debugging overhead. And again for that developer, they provide very, very small gains.
I think the calculus changes if that developer starts to run multiple services on multiple servers, wants to keep doing that for years, and needs high uptime. I have a bunch of personal services I run in VMs with Chef, and I'm excited to convert that over to Kubernetes, as it will make future OS upgrades and other maintenance easier. But my old setup ran for something like 6 years and it was just fine. For hobbyists whose hobbies don't include playing with cluster-scale ops tooling, I think it's perfectly fine to ignore Kubernetes. It's the new hotness, but it doesn't provide much value for them yet. They can wait a few years; by then the tooling will surely have improved for low-end installs.