Well, California is 423'970 km². And Germany is 357' 684 km². I only use OsmAnd, not CoMaps. So almost the same size. The street card of Germany is 2848 MB, so even larger than the number you gave.

We also have cards for the places we live, e.g. I have the "full" map (not just streets) of Hessen, one of the 16 federal states. And that is only 485 MB. If that would be too much for me, I could also only download the governmental areas of Darmstadt, Gießen or Kassel (roughtly southern Hessen, middle Hessen, northern Hessen). But that is, in the OsmAnd case, also the case for California. You can download all of it, or or several of 16 parts.

Also: you can't compare OpenStreetMap with the detail of this old CD-ROM or printed maps. It contains WAY more data. Are you old enough to know the times where you bought a city plan if you visited some city? Well, this OsmAnd/CoMaps data set has a very details city map of all cities. And of all villages. And of about any dwelling. In OsmAnd, you cans search for almost everything, even esoteric things. Example: if you search for "Kneipp treading pool" you find them. And usually they are nice picknick areas, too. Try that with a printed map.

I personally experience you "EVERY MONTH" issue. My map of "Hessen" was last downloaded half a year ago --- I do this manually, and only every so often. OsmAnd allows that.

And if I would experience it ... I'd rather care. We have high speed DSL and glass fiber with 1000 MB/s in Germany, so 2 MB is almost nothing these days.

Still I would not recommend OsmAnd to everyone, e.g. not to "Aunt Mary". It has a clunkier, more techy UI. It isn't for everyone.