I would argue the eventual "bogged down" feel of a Rails application isn't ruby itself. It's rather the abuse the database takes because ActiveRecord allows you to lazy load records so easily by abstracting SQL calls, so you're hitting the database many times per request and not realizing it until you get bitten. There is an option to disable lazy loading at a project level, but I've run into gems that assume it's enabled.

For comparison, elixir's Ecto doesn't allow lazy loading