It could be a form of bundling, tacit veritcal integratation, magin squeeze , price discrimination, tie-ins etc.

Various tricks oligopolistic companies use to prevent competition from bidding prices down - trying to extract a bit of extra profit. The harm is that people are paying more than they might - or for extra features they cant opt out of than they would in a free or open market. Likely the harm is very diffuse and no one person is all that bothered to be paying 10% more or whatever, but it all adds up.

Anti-trust regulators are so weak they don't really have to try though. TBF it's very hard to prove this stuff in court even if there was a political will to improve competition to benefit consumers.