This applies even without the non-competes - it takes time to set up a new company and gain marketshare, so even without non-competes the monopoly is successfully kicking the can down the road. And every extra year of monopoly is another years' worth of price-gouging profits, so repeatedly buying out competitors can be worthwhile.
I wondered why noone else had since tried to do a book discovery engine at an industrial-scale to compete with Amazon. Here's one 2019 list of book-discovery sites: "Broke By Books: 20 Great Book Websites for Finding What to Read Next" [0]
and here's one analysis [1] of the key things Goodreads added value for Amazon: Kindle integration (social, ratings), a storefront that lets them push Kindle as the preferred version for purchases (or else Audible, or Prime and Kindle Unlimited subscription programs), data that can be mined from user reviews and ratings to power ML for better recommendations, understanding users' book- and reading-habits, rich content to increase interaction and hold user attention...
I also wondered why the Goodreads cofounders hadn't gone and founded other companies, in other sectors.
[0]: https://brokebybooks.com/20-great-book-websites-for-finding-...
[1]: "Who owns Goodreads?" https://bookriot.com/who-owns-goodreads/
I was surprised neither of them left sooner than that to do anything new, in any sector.
Goodreads' Otis Chandler in 2021 invested [0] in BookClub [1] ("building actionable learning cultures through books, for teams").
And Elizabeth Khuri [2] and Chandler both also invested in Looped [3] (a more engaged and interactive livestreaming event service for concerts, comedy and other entertainment)
[0]: https://www.crunchbase.com/person/otis-chandler
[1]: https://www.crunchbase.com/organization/bookclub
[2]: https://www.crunchbase.com/person/elizabeth-khuri
[3]: https://www.crunchbase.com/organization/looped-6aae