Slightly more athletic?
Look at the PG's, the most athletic PG of the 80's and early 90's was Kevin Johnson who is as athletic as Jeff Teague. Today, you got superfreaks like

and

not to mention speed demons all over the league. Come on son. That's crazy talk for real.
What about Devin Harris, Jason Kidd, Derrick Fisher,Kirk Hinrich,Rondo,steve nash,Jameer Nelson,Jeremy Lynn, ect ect ect. Plus half these speed freaks you talk about are brain dead with a wack J and wouldnt even make it through the college game to get to the NBA
Look at SG: In the 90's you had the Wittman, Tipuka, Ehlo, Miller, Hornecek, Henderson, Gill, Dumars of the world. Most usually loot footed defenders who are great shooters. Outside of Drexler, Harper, and Jordan who are great athletes who can score.
Reddikk,Kevin Martin old ass Vince Carter, James Harden, Bradley Beal,Nick Young,Ray Allen, Jason Terry,bellineli are all in the top 25 scoreres at SG
Today you either have great athletes who can either score or defend, the great ones can do both. All defenders have excellent length and lateral quickness, the scorers and score at an elite level and the shooters have to be specialist because of the ability to be defended and taken out of the game as starters.
Man to man D is garbage (with a few exceptions)in todays game because A) its not taught early and often enough and B) the rules are set in a way to cater to the offensive player even more to the superstar offensive player
To say today doesn't have better athletes is
Didnt say they were not better just saying that the gap isnt anywhere close to as large as you try and make it seem and that there were plenty of guys in the 80's and 90's (and earlier) with the same level of athletisism as guys today