> Well that would be inefficient. For each command you run the kernel has to read the file, detect that it has a shebang, parse the shebang line, and then finally load the actual executable in memory.

Those that exist today would, but no kernel would have to work like that.

Once you've agreed that monolithic kernels have merits, you've accepted that the kernel can do whatever it wants to make this efficient—including being complicit in this scheme and leapfrogging over most of what you just described.