This is actually a big thing we invest in at my current company: candidate experience and consequently a high Glassdoor rating. After focusing on it for years the company has one of the top ratings on Glassdoor (top 100 or 200 I forget). It’s a big differentiator when you’re not a big company and not a recognized brand. I think for FAANG companies they can get away with it because despite a poor experience, the actual job and pay/perks they offer are extremely desirable. Sad because, like you say, it’s not hard to see and make an impact on improving.