If so many companies are such a disaster, why isn't someone founding a startup that says "We won't do any of that crap here" and eats said companies' lunch?

Might be such startups are unstable, because once the lunch starts getting eaten, the founders are instantly offered "F-you money" to sell their company, at which point it gets rolled into a disaster company. Or it loses its incentives past a certain size.

Rare indeed is a company whose founder(s) both (a) refuses to sell for a generous valuation and (b) actively put the brakes on aggressive growth out of wariness it will destroy the company yet (c) still sees the company to success.

You just answered your own incendiary question: because the systems incentivize bad behaviors for individual success over the health, longevity, or success of the organization and its members.

It takes hard work to ignore the easy exits in favor of building a healthy organization designed to withstand the temptations of the modern business cycle. You're not building a mere startup or business, you're building an institution, and that's an infinitely harder job that doesn't pay nearly as well - though it often has far more substantial impacts.

So many people are obsessed with striking it rich via individual success, that they're blind to the reality that we already have the resources and technologies to ensure everyone can enjoy modest success, if we discipline exploitation for personal gain. It's why part of founding a startup nowadays is literally developing an exit strategy, rather than a successor plan: the goal is for the founders to succeed, not the business, and definitely not its customers.