Wasn't SEO, it was a Google's "Suggest over Search" strategy, followed by the completely predictable bastardization of organic results by internal groups.
Biz ops says increasing revenue for [random Google bs] by ranking Y over Z in the results, so it happens. M&A says Rotten Tomatoes won't give us all their data, their users and their firstborns so they won't show up, even on page 2.
This is literally what antitrust was created for. Companies do this naturally when they get too successful, it's on us to remind them who pays the bills.
By us I mean the US govt so we're basically fucked.