These are hypotheticals, but Microsoft really was caught by exactly this mechanic in mobile a decade later - no-one made apps for Window Phone because it had no users, and it had no users because no-one wrote apps for it, and all the power Microsoft had in Office and Windows meant nothing. 

Microsoft might have been doing all sorts of mean and sneaky things, but people used Windows and Office because of network effects, and those network effects were and are internal to each product. People used Windows because it had the software and people wrote software for Windows because it had the users, and that had very little to do with Office.