I don't think outside of MSX Microsoft have or have had much relevance to gaming, Xbox even less. Gamecube had done better in 6th gen and PS3 had done better in 7th if Xbox hadn't existed. However, I think at least some of the last decade's entrants would have had at least moderate success without Xbox.
Ei Kiinasti.
Eikä Japanisti.
Vaan pannaan jalalla koreasti.
Nintendo games sell only on Nintendo system.