You can't see both Mexico and Europe on a globe at the same time, but you can on a map. Globes are great, but the ones you see in most households are quite small with very little detail.
Atlases can help by showing geographical regions in appropriate projections on each page, but again you can't easily see full page appropriate projections of both Europe and Mexico at the same time because they'll be on far separated pages.
Sure it's possible to do that, but this discussion is about the experience people actually have with maps and how that affects their expectations. I don't think it's common for people to do that.
I actually did, but they both so distorted by perspective that I doubt many people have done that to build an understanding of their relative size in practice.
You can do, but how many people actually do that in practice when building an understanding of the relative size of regions, relative to looking at them on a flat map?
Atlases can help by showing geographical regions in appropriate projections on each page, but again you can't easily see full page appropriate projections of both Europe and Mexico at the same time because they'll be on far separated pages.