Because there are dozens of competing standards and none is clearly superior to the others, because it boils down to being a really, really simple problem: Enco

Because there are dozens of competing standards and none is clearly superior to the others, because it boils down to being a really, really simple problem: Encode two numbers. (That's also why there are so many standards - it's simple so everyone wants to bikeshed). There will be no "truly superior" solution, just one that has optimized for different properties. Plus codes aka Open Location Codes are the biggest "modern" one that seems to have seen some adoption mainly because Google is pushing it (example: "VXQ7+QV Washington DC" or "87C4VXQ7+QV"). Otherwise, decimal coordinates are pretty universal (example: "38.88948,-77.03527" or "38.88948 N, 77.03527 W"). What3words (example: "///jugendliebe.rechtsschutz.mauerreste" or "///cabin.flops.gravel") has other advantages and disadvantages, but running it as a closed project (and the requirement to ship megabytes of databases) kinda killed the project before it started. But even without that showstopper it wouldn't be clearly superior vs. other systems, including the old and proven "two numbers, written as numbers", which is good enough and works almost everywhere.