Seems like given enough time, any company will lose whatever value it tried to uphold in the past in favor of shareholders.

Once it reaches that point, every business optimization is in detriment of either the final user or society, quite often both.

Don't the founders have a majority of the voting stock? Do they have a legal obligation to "maximize shareholder value" for the other shareholders?

Shareholders= You and your parents and your grandparents retirement.

This need to have 7-13% yearly returns force companies to grind their employees and customers.

I like capitalism, but I can easily see capitalism doing evil things to create short term profit.

"I can easily see" sounds like it's a hypothetical, but destruction of real value for short term monetary gain is plainly visible all around. I've probably ran into 1000s of real world examples.