I think Google has done a lot to get us away from different projections with EPSG 3857 and 4326. It's both a blessing (because you can expect most geographic data to be available in that format) and a curse (because 3857 is kind of a shitty projection and the standardization sort of disincentivizes people to learn about the intricacies of coordinate representation).
Totally agree about prevalence of 4326/3857 as a net positive. Given I still find projection/coordinate representation a little tricky, I think the chances that widespread education on the subject would ever exist to be pretty slim. Might as well just have a good default.
Displaying state/country level data using EPSG:4326 isn't great, thankfully it doesn't happen often.
