I think the introduction of the "light mode" "dark mode" distinction actually made things worse.

As a designer, before you had the whole spectrum to work with so you could have dark areas in light areas in dark areas, etc.

Now, if you start with thinking "I'm working on a light-mode theme" you're suddenly restricted to only half the gamut for backgrounds, and you end up spreading things out more within that (more white, in order to contrast the slightly darker white). Plus you need to make it visually distinct from "dark mode" which means you're probably aiming for less than 50% gamut.

I think it's a mental trap.

Edit: And it's made worse by the fact that browsers now have built in light/dark mode preferences, standardizing this framing. So if you create something that doesn't fit in the light/dark boxes, you worry about users complaining of you not respecting their browser preferences.