But the East has been mostly bad since the early 00’s. The West was trash in the 80’s but it’s been good for the most part since then.
When is going to ebb and flow?
No one can say.
But here's a little history about the MLB all Star game to put things in perspective:
Ninety-three All-Star Games have been played (including two games per year from 1959–1962), with the AL leading 47-44–2. The All-Star Game has seen several "eras" in which one league tended to dominate. From 1933 to 1949, the American League won 12 of the first 16. The National League dominated from 1950 to 1987, going 33–8–1. This included a stretch from 1963 to 1982 when it won 19 of 20, including 11 in a row from 1972 to 1982. Since 1988, the American League has dominated, going 27–7–1, including a 13-game unbeaten streak (12–0–1) from 1997 to 2009.
Any team, any "conference" can go on long runs of dominance or ineptitude.