Weinstein, Cosby, and Polanski are on the permabanned list, they just did it quietly in 2017 and 2018. Another guy named Carmine Caridi was banned for selling Oscar screeners that bootleggers then copied. If you ever watched NYPD Blue, he was Vince, the old white haired union delegate detective on the show.
There are a couple of others too, but they are behind the scenes guys. Richard Gere, Susan Sarandon, and Tim Robbins were banned for a little while for promoting political causes on stage, but let back after a few years.
I remember NYPD Blue, but not well enough to remember that guy.
Regarding Tim Robbins and the others - they promoted political causes and got temporarily banned?
Isn't the Oscars almost all politics anyway?
I was looking online, and apparently the Oscars started getting under 50M viewers in 2002, and this year, hit under 10M for the first or second time.
I vividly recall an episode of Entertainment Tonight from 1994 [possibly 1995] that said the expected audience for the Oscars was ONE BILLION.
There are many reasons for that, but the Oscars being glorified propaganda is not helping their ratings.
It's amazing how many views the Will Smith slap video got! Almost 95M views! Well into the 100M+ range if you count all the other videos that covered it.

Haha, way more than the Oscars: