I get where you're going with this and think it's an interesting debate.
I think you're underestimating the amount of PG's that were really good as below the rim guys 25 years ago - Gary Payton, Mark Jackson, Terrell Brandon, Mark Price, Rod Strickland, Damon Stoudamire, Greg Anthony, Avery Johnson, etc. Is Trae Young any different now than Mahmoud Abdul-Rauf was then?
Perception is also another wild card - as you pointed out Kevin Durant didn't test well as an athlete (but is considered athletic), but you point out James Harden as a average athlete even though he tested great athletically (even though he just looks kind of fat)
I think it's also not just shooting 3's - it's also 3&D - longs guys that are athletic enough to switch and defend multiple positions while being able to shoot 3's.
I would say if you're just comparing the top guys, there's more athletic freaks in the game today - LeBron, Giannis, Westbrook, Zion, AD, etc.
And I think if you look at full starting lineups for teams then vs now - there's a lot more players you'd forget about from them that really weren't great athletes that played major roles on teams.