In a YouTube video about the history of OS/2, I learned that ole Microsoft back in the 1990s before their mob tactics were curtailed, used to send suited thugs to Japanese PC manufacturers to chastise them for even offering users the mere option of buying PCs with OS/2 instead of Windows..

Could such practices have stifled the innovation and growth within the Japanese PC industry?

They did have some takes of their own on the PC platform with that unique Japanese flavor, in series like the PC-8800/PC-98, FM Towns, etc.:

https://en.wikipedia.org/wiki/PC-8800_series

https://en.wikipedia.org/wiki/PC-98

https://en.wikipedia.org/wiki/FM_Towns

Who knows what more they could've done if Windows 95 hadn't smothered everything under the sun? Like the ill-deserved demise of the Commodore Amiga, this seems like a failure of politics than merit.