It's a standard sort of thing.

The idea is that a non-manager has minimal ability to affect the company's bottom line. While those further up have the ability (and now have the incentive) to affect the profit of their division or the whole company.

So a worker gets 100k with a 10% bonus, his boss gets $120k with a 40 percent bonus etc. In a good year the boss will get almost twice the worker but in a bad year he will make just 20% more.

Yes, 4x is a big gap, not just % wise, but dollar wise too. I'm sure they don't talk about it during the interview. But if somehow that information slipped in during interview, I would honestly just thank them for the time and walk out because I would never work for a company that believes in the large gap of the output of the 2 groups.

The compensation progression for a manager generally consists of a slow (if any growth) in base salary and most compensation increases come from stock and bonus. I believe this is generally the same for high level ICs. Some companies make it explicit that there is an IC level that corresponds to each manager level and both have the same compensation structure.

0.0004% is 4x 0.0001%. If it's a small amount then 4x really doesn't matter.