I don’t disagree – in fact, I was the one who first added an old_name=* to this bay in Russia to reflect its century-long identity as the Gulf of America. You can’t make this stuff up! However, indicating either Denali or Mount McKinley as the old name of the mountain in Alaska would be an oversimplification, even if you qualify it by dates and languages. Better to leave things a little vague, to avoid setting unsatisfiable expectations.
Wikidata does a still imperfect but better job of modeling the nuance using qualifiers, an element of expressiveness that OSM’s data model unfortunately doesn’t provide. In its own way, OHM can also tell the same story but in a form factor close enough to OSM to give OSM some breathing room.
The date-qualified tags are at best misleading. They paper over the longstanding differences between official and colloquial usage, between federal and local usage, between English and non-English speakers, and between native-born Alaskans and expats from McKinley’s home state of Ohio, and nowadays also between left-wing and right-wing discourse. To say that a name is “old” is to delegitimize it to a significant extent. In this geopolitical dispute with many cross-currents, you won’t find a better way to come across as non-neutral and political.
I don’t know about Mexico or Cuba, but in the United States, the slash delimiter is quite controversial (and I disagree with it). If you’d like to add another dispute to the pile, here’s a starting point: