It seems unlikely to me that Hollywood has an age discrimination issue.
Oh they certainly do have an age discrimination issue, particularly for female actresses.
Society has an age discrimination issue. Most of us, even women, would rather look at a fresh-faced young girl than at a woman with lines on her face. We'd rather look at perky boobs than saggy ones. Is it even possible to fix the problem of age bias in Hollywood, and if so, would that actually help address the problem of age discrimination in society? Or would there just be a lot of bitching about how feminist laws are compromising entertainment, ala Ghostbusters? (I don't have an opinion on that movie, which I haven't seen; I'm only characterizing the complaints.)
If an actor doesn't look the age for a part, they're not going to get the role.
That might have some credibility if they didn't also hire actresses who do not look the role at all. See Emma Stone in Aloha. See whitewashing. Same thing happens with them hiring actresses who are FAR too young for the role they are playing.
Yeah, I thought that was a bullshit argument, too. The truth is that they're going to hire the prettiest, most popular actress to play the role, and part of that means hiring the youngest one that can more or less carry it off because that's what puts asses in seats. I shouldn't have to be the one to tell you this, either. The degree to which youth equals beauty has been explored nigh unto death by everyone and their mom, especially as she ages.