My experience is completely different from yours in regards to every single point you make. Working at a big company (amazon) has increased my salary significantly, made me better technically, and noticeably made it easier for me to find a job elsewhere afterwards (this could be because my technical skill were better afterwards, and I had more experience). Additionally, I actually loved my team at Amazon. My manager was incredibly empathetic and caring, far more than any managers I have had at smaller companies before. I just wanted to provide a different perspective, and show that generalizing about companies, especially large ones, is a bad idea and often grossly incorrect. Your experience and the people you talked to (likely) represent a very small part of the whole company.