I think you can argue that current day MS is a little more afraid of anti-trust action than 1990s MS. Game developers were legitimately scared that MS was going to do this for windows and start taking their own 30% cuts from all PC games. I'm not sure if Valve confirmed it, but it seems likely that SteamOS/Steam machines were at least partly a backup plan for ensuring there was a place to sell games without MS skimming off the top.