Why would they? It's FrEE maRKeT. Google can point to Edge and Safari as proof that they don't have a monopoly on browsers, so no anti-trust issue there no sireee. The fact that Edge is based on Chromium does not factor into this (in fact the EU loves it, just look at what they did to "liberalize" the electricity market, aside from some extremely anecdotal stories, it's all companies whose only job is to build a website and the fiscal "infrastructure" to buy energy from state-controlled producers to resell it at a markup using state-controlled energy distributors, but hey there is a private middleman so it's liberal and the innovation/investment dividends will pay out any year now... any year...).

The concept of the WWW being supported by free, standard, interoperable protocols was never codified into law. Despite how much good it has done so many industries to have a common free interoperable tech stack, it doesn't have to be this way; the French Minitel was a walled garden built by France Telecom, and that was 100% legal, because interoperability is not a legal requirement. The Apple Store and Game Consoles work under the same principle, you basically can't sell anything on there without abiding by some asinine rules (Apple has had some issues but IIRC that has to do with them abusing their monopoly position to extract 30 % of all sales, not with the fact that they have an exclusive App Store to begin with).

Also this whole bullshit is not new and was never legally challenged because there is no case. For years you could not even browse instagram in your browser because they "only supported the mobile app", which was a blatant way to force you into a walled garden where they can force you to watch as many ads as they want and where scraping is much harder.