It's a flawed idea because it's harder to do? Or because some people want all big-budget games to be all things to everyone and that isn't inherently flawed either? I'm not trying to shit on games evolving. I would just like to be able to roleplay in games that are described as roleplaying games. Why is that a flawed idea?
If an X game has rpg elements but is not designed around roleplaying, then why don't we just call it an X game with roleplaying elements, rather than a roleplaying game. One suggests a different core with rpg features, while one suggests a roleplaying core.
Just to be clear, I'm not trying to imply that you're shitting on anything - I think this is a fun topic to discuss.
I think it's a flawed idea because the functional solution already exists and you present it in your OP (and in the quoted message). Even if you wanted to filter games through a narrow lens of specifically literal "roleplaying", you'd still end up with games that have that, but play extremely differently. I'm not sure if I'm matching your definition but I'd propose something like Neverwinter Nights, The Witcher, Mass Effect, and Skyrim. All are heavily 'roleplaying' in the literal sense, but they play extremely differently. So if you came to me and asked me for suggestions for an RPG, I'd still end up going through variations on the term RPG. cRPG, open-world RPG, RPG with 3rd person shooting etc. I would tie this to the fact that for videogames, genres tend to have implications for tone, story, visuals, camera, gameplay, specific game mechanics and so on. So I don't believe we could ever satisfyingly categorise and recommend games solely based on 'RPG' anyway. But as a single filter among a few others, sure, RPG could be used in a more pure sense.
In one of your posts you mention games borrowing RPG elements, and in that area I do completely agree. I think it's great that there is tons of genre bending and blending and games, but it's not always positive. I feel some AAA games get homogenised with 'RPG elements' to a level where it is detrimental to the game (thinking of games like Avengers, Gotham Knights, Suicide Squad). But in those cases, I think you've also already described the solution; X type of game with these types of RPG elements. Returning to my own post, I'd probably describe FFXVI with phrases like 'JPRG ', 'Story-Driven Action RPG'.