Earlier quoted context omitted.
But the point is that's Microsoft's choice. They have the money to compete and jumpstart Bing with default placements and reap the ad dollars and build Bing into a serious competitor. If they don't want to compete because they think investing money in Xbox will have a higher return, that's their decision (and maybe their mistake). It's not Google's fault.
What is missing in this discussion is the fact -- explicitly called out by the court in the opinion, see e.g. https://news.ycombinator.com/item?id=45109999 -- that Google Search is so good because it gets so much search traffic and, critically, user interaction data such as clicks, dwell time and even hovers on search results, which it mines to figure out better rankings. Unless competitors get that kind of traffic A…
If Bing's market share is 4%, then Bing still gets tons of user interaction data.
Bing gets something like 100M queries per day. That's more than enough data.
Microsoft has all the choice. They have the money. They can invest, like Google has invested and continues to invest. You don't get these things for free.
So yes, it is absolutely a choice. A small startup may be disadvantaged. But not Microsoft with over 15 years of user data from Bing.