Mirrors my experience, and it's funny you mention busybox: I just discovered busybox's ability to serve via `busybox httpd -p 9000 -h . -f -v` with a `cgi-bin` folder dropped in the current directory.
I already write Python services using Bottle that function both as a standalone server and as a CGI script, and I've been updating them to work with busybox's more constrained CGI environment (basically being able to handle the lack of .htaccess rewrite rules).
I definitely see a chance for simple deployment tools to make a resurgence as we create more one-off/disposable/personal software, and the low system requirements for something like busybox + lua stack are extremely minimal, which fits well with the current DDR4-is-good-enough zeitgeist. I'm running them on an old Raspberry Pi 2B and it's plenty performant for the ~10 people that access it regularly.
Instead of busybox+Lua, I just use TurboLua:
https://turbo.readthedocs.io/en/latest/
Event driven, fast, all the networking basics in place including http, mustache templates and encryption, light and small executable, very nice for embedded applications, signals and fd handling built-in, very easy to use…
Have used it very successfully for million-dollar projects, including some scientific applications running on limited-resource systems (512 megs of RAM) ..
Was very, very easy to add C functions to interface with the web front-end, libffi is great for this purpose, but its also very easy to extend as a standard, well-written Lua/C application ..