Microsoft argued that this was not anti-competitive; they claimed the discount simply represented Microsoft not having to keep track of individual licences and that OEMs where free to buy licences individually instead. They lost that argument because it was found that since Windows already had a majority market share (for the time being) an OEM had to load Windows on a majority of their systems to satisfy consumers. Because of the pricing scheme OEMs could not be competitive with other OEMs if they took option 2, forcing them into 3 where Microsoft's terms made it uncompetitive to sell PCs with another operating systems. So Microsoft was convicted under the Sherman Antitrust Act.
Let's look at Google and its club the Open Handset Alliance (OHA):
The official Android distribution can be seen as something wanted by the majority of customers (looking for a non-Apple/Microsoft or a inexpensive phone) at this time (unless you have something else big enough to get people to come to you, like Amazon) so most Android/android OEMs would be giving up the majority of their customers if they dumped official Android entirely; that removes option 1. Much like the licence discount a membership in the OHA represents a major competitive advantage - the OEMs are already way behind in keeping official Android up to date in their design and production pipelines even with that inside track and help from Google. An OEM on its own trying to make an official Android device is thus at a large disadvantage against OEMs that are part of the OHA. This makes option 2 uncompetitive, forcing any serious OEM into option 3. Option 3 goes even farther then Microsoft in the 90s - it doesn't just apply a tax, it outright bans the alternative.
So does the same 90s logic applied by the court - that regardless of Microsoft/Google's excuse for the 3 choices it isn't really a choice at all, and that the only viable choice blocks competition - still apply today?
Space tells matter how to move and matter tells space how to curve. -- Wheeler