TPC clearly knew about the nostalgia factor. It's why they pushed the "original 151" so much, down to Pokemon Go launching with solely them. Normies know about the original 151, maybe the new Pokemon from Gold/Silver, and a few of the highly marketed ones or furbait from the newer generations.
Sword and Shield doesn't even have all 3 of the original starters. Many fan favorites and iconic Pokemon were cut as well. Even some of the heavily marketed Pokemon from the past who made appearances in spin-off titles or crossover titles were gone. Then there's the fact that older Pokemon and moves were cut, especially when Game Freak made sure to avoid a repeat of the issue where Pokemon from Gens 1-2 were not transferable to 3+ for years.
Cyber Sleuth also didn't have every single Digimon and it makes sense when there's around
1,300 with many being reskins/variants. But they made sure to cover the bases when it came to the most popular Digimon. Sword and Shield couldn't be bothered to do that.