It's because Lebron went west.
Yep that was definitely a take off yours that aged bad. Glad you can actually laugh about it. The real reason the east is less mediocre is the development of players. Trae young and other young players developing line John Collins made hawks not mediocre. Randles ascension into an all nba player made knicks not horrible. Zach lavine becoming an all star level talent made Chicago competitive. Toronto having development from siakem, og and van fleet has stopped them from becoming pathetic after leonard left. The celtics dispersing talent to Charlotte (rozier and hayward) and nets has made the hornets competitive.
Honestly, I don't know that the 2019 bottom teams in the east are really any worse than they are today. The 19 Hornets, Heat, and Wizards didn't make the playoffs and were probably better than 9-11 right now. The Hawks were really young that year, but had the talent base in place. The Bulls were just super injured (LaVine's 63 games were 4th most on the team and only 1 guy played more than 74 games).
The two best teams in the sport are in the East right now, which really helps, and there are a few other teams that could certainly make a run to the ECF if they landed the right match-ups. And there are more big stars in general in the East right now (which was the point I was making in my stars going east thread), but with Philly the way it is, there really are only 2 teams that look like Finals teams in the conference, where I think you could make reasonable arguments for 4 or 5 teams in the West.
If you look at the SI top 100 only 4 players from the East were in the top 10 (Durant, Giannis, Harden, Embiid). 5 of the next 10 and then 5 of the next 10, but only Bam was in the 21-25 range. So of SI's top 25 players next year only 10 were in the East, with 15 out West. That all makes sense when you look at the Futures and what not where only 2 of the top 7 in odds are in the East (at least at the site I was looking at), but Brooklyn was 1 and Milwaukee was 3 (the Lakers were 2), after the Bucks it was the Clippers, Suns, Warriors, and Jazz before the Sixers at 8, Nuggets at 9, and Mavericks at 10. Then you get the Hawks, Heat, Celtics before another West run of Blazers, Pelicans, Grizzlies. So only 6 of the top 16 teams by odds to win the title are in the East.