I think I'm one of those people who saw them as very VERY different things. Maybe I was just young enough to not see the similarities? Or just too OCD? (I would never EVER have mixed 3.0 and 3.5 material either). I had no problem with 4E and Essentials, though. I don't know if that's a difference in material, or a difference in ME.
Yeah, I guess if you want to call a fully backwards compatible update to the core books 6E, even if WotC doesn't brand it as that and one can still play everything published for 5E with little to no translation, AND it takes relatively little work for WotC's design team to produce... I guess THAT product could be coming for 2024, sure.