Re: North of 85%...
Tell me - at what point does the definition of "anticompetitive monopoly" start?
Remember when Microsoft needed to save Apple to avoid a monopoly?
Microsoft are already putting Office products on Android and, importantly, Google has almost no market share in actual phones. So long as Google encourages third party developers and allows OEMs to customise Android, and so long as Facebook is an equally big data slurper, they might well be OK. At least in the US.
If Trump continues to spout nationalism, of course, at some point other countries might decide the US has a monopoly on certain aspects of IT and start to act against them. But by the time it gets to that point he may well be history. Or, if the war with China heats up enough, geography.