Because corporations are autocratic. All power is top down. Make corporations democratic with bottom up power structures, and the opposite will happen. Leadership will face blame for everything, and the bottom rung will never.
Delegating authority is a velocity/democracy tradeoff. Polling 100k people about where to get lunch doesn't work.
So over time, any time someone does something that might be seen as unjust, if it's within the error bars for "unusual but not a hard line", shifts the line more and more, especially if the people in question are good at controlling what the people above them hear, or calling in favors to shield themselves, until you wind up with sentences like "well of course they got fired, they were working on $THAT_PROJECT, and everyone knows $MANAGER hates $THAT_PROJECT".
To be less reductive, companies are owned by capitalists and they prefer autocracy for obvious reasons.
2) Cooperatives are what you are looking for. Why aren't there more of them? No founder ever wants to share the initial investment. Is it a universal human weakness? I don't know. Why aren't the very few that exist growing to be more successful than a small local niche thing? Probably because democracies work best for small groups and progresively degrade as the number of people increase.
3) It works as indended. The people that are (temporarily) interested in the success of the organization, and with the power to change it if it looks like it's failing, are not interested in long-term success. As long as company's stock can be sold, only short term profits matter.
Owners of family businesses are more likely to listen to low level employees, but they're still autoritarian.