I actually have an opinion of my own about this, and that's the fact that what we fans view as "the glory days of Pokémon" is always changing. We saw this during the heart of the 3DS era, when the DS games were rising in popularity, sure, but the third generation games were also at their most popular point to date. I think Game Freak knows about this trend, which is why ORAS coming out in Generation 6 is such a good fit. Just to get the discussion rolling, here's what I'd say "the best Pokémon games were according to the fanbase during every time period as of Gen 3.I ask this as a legitimate question, not a rhetorical one - how do you explain the stretch from 2008-2012? There were four main series games produced during this four year period - Pt, HGSS, BW, B2W2. Those might be the four best games in the series (though I think Emerald deserves consideration).
Was the move to 3D that much of a chore for GF that quality was compromised so badly? The pressure that comes from a yearly release seems like more of an excuse than an explanation for a company of GF's size, given their resources. Once upon a time, yearly releases did nothing to stop the quality of games GF was churning out during the Golden Age of 2008-2012. I just have a hard time believing that that's the root cause of the problem now.
Early 2000s: The resetting brought with Ruby & Sapphire (and Colloseum, I suppose) quickly gave people a yearning for the days of Kanto
Mid 2000s: With Kanto, Hoenn, and Orre all being covered by current entries, interest in the Johto region increased again
Late 2000s: Similar to the last period, with Johto interest at an all-time high as well the start of consistent increase of GameCube interest
Early 2010s: Hardcore Gen 5 fans may remember this as the "Hoenn Confirmed" era
Mid 2010s: General interest in the Gen 4 games increased this time (people also started wondering what happened to the Ranger series)
Late 2010s: 20th anniversary hype helped out Kanto quite a bit for newer fans, and Sinnoh only got more popular too
Early 2020s: Where we are now, the general consensus is that Johto, Hoenn (lack of ORAS on Switch), and Unova need the most attention
See the pattern here? We're going to see this until the end of time, and that's why Pokémon fans will always buy remakes even if they turn out like ILCA-inspired garbage along the lines of BDSP.