This is sway, i3 on wayland, a tilling window manager. Not some commercial piece of software that has to target the lowest common denominator to survive in the market. It's meant so that you configure it and it's very configurable. So it doesn't any defaults bar what's needed to launch the manager. The rest is up to you.
Configurability is great, but that isn't an excuse for having poor defaults. A child comment to yours mentions that Sway now uses a heuristic to find a "reasonable" default scaling factor, so it appears that Sway currently does the right thing.
