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.