You are not wrong. Docker (paired with Kamal in Rails world) would simplify a few bits of the setup. But not all. The reason I haven't switched is:
1. my lack of experience with running docker in production
2. don't fix something if it ain't broken
But I'm planning to revisit it when my current LTS version runs out of support. Also, Kamal defaults change a few core pieces (caddy vs nginx, puma vs passenger) so there's a bit of extra learning curve). Oh and you'd still need to harden the server and keep it up to date.
1. my lack of experience with running docker in production
2. don't fix something if it ain't broken
But I'm planning to revisit it when my current LTS version runs out of support. Also, Kamal defaults change a few core pieces (caddy vs nginx, puma vs passenger) so there's a bit of extra learning curve). Oh and you'd still need to harden the server and keep it up to date.