Amazon could become a good place to start as a junior moving on to a proper remote work at Google/Microsoft/Facebook/etc.
Many parts of it can be a bad place to work. But it's a huge company. There are some parts doing cutting edge work as well that you won't get access to at other companies. But to your point, the likelihood that a junior engineer will get access to that is slim, and so your assertion holds.
Amazon's policy is exactly the same as Microsoft. Is Google proper remote now?