Amazon is a trust, not yet a monopoly. There is an inherent conflict of interest, and lack of recourse (forced arbitration), between Amazon marketplace sellers and Amazon the e-commerce store. Likewise between AWS customers and Amazon the e-commerce store and advertising network. By any reasonable consumer standards, AWS should be split off into a separate company. The pervasive surveillance and continual scandals surrounding Ring's handling of user data, when taken in context of Amazon's collection of user data from the e-commerce store, advertising network, Alexa, other Amazon business units, and purchased third party data, mean that Amazon should never have been allowed to acquire Ring in the first place. If the Department of Justice Antitrust Division had not been completely captured by corporate interests, they would be in the process of litigating to undo this acquisition right now.

Have we seen companies get split off in similar circumstances in the past?

Not exactly the same, but in the 90's we almost split up Microsoft to two separate divisions: a company that builds the operating system, and a company that builds user-space applications.

This was because, during the browser wars of the 90s, Microsoft was purposefully gimping competing browsers at the OS level like Netscape Navigator so as to encourage people to use Internet Explorer.

The textbook case studies would be the break up of Bell Telephone Company [1] or Standard Oil [2].

[1] https://en.wikipedia.org/wiki/Breakup_of_the_Bell_System

[2] https://en.wikipedia.org/wiki/Standard_Oil_Co._of_New_Jersey...

They're buying competing booksellers, which is by definition anti-competitive. https://en.wikipedia.org/wiki/List_of_mergers_and_acquisitio...