Seconding this, light themes cripple syntax highlighting, which in turn makes it far more annoying to quickly scan through code and glean structure. You can make up for this to some degree with text decorations, but, well, with dark schemes you have that too.
I have about 1500 lines in my VSCode settings.json dedicated to custom syntax highlighting and text decorations (this could be trimmed, some is from before the days of semantic highlighting), but regardless, the amount of differentiation I can achieve with this is simply not possible on a light background. I've tried! (Solarized light is a nice theme though)