Xbox was always consumer and is massive. A huge chunk of the Windows line was always about consumers. The office line straddled both. Hotmail was consumer first.
Even with Windows, which is their most successful consumer product, its success can arguably be attributed to the fact that Microsoft essentially has a 100% market dominance on computers sold under $1,000. Would that product be as successful if it faced competent competition? We really can't say for certain.
Office has historically seen consumer success (however I suspect the rise of G Suite has significantly curtailed that), but that's only because Office has been a necessity if you want to interact with business documents (which are typically .docx and MS Office files).
The common theme here is that, with the exception of Xbox, Microsoft's consumer products only seem to see success when consumers have no other options.
What consumer successes has Microsoft had recently other than Surface?
MS has what I call the 6 versions rule. v1 do not get, v2 interesting toy, v3 hey kinda usable, v4 get this thing it is cool, v5 they manage to mess it up badly, v6 just kinda put that back but not quite. They then toggle between v5 and v6.
It will catapault one of their subsidiaries into the heart of that.
Remember they used to 'own the world' through IE, very much a consumer product, and that didn't shape them.
They own Skype, one of the world's most prominent p2p communication tools, and screwed that up.
Microsoft has done enterprise so well for so long but has always struggled on 'consumer tech' outside of its Windows OS. Acquiring a social media platform is going to catapault it into the heart of consumer tech.
Question is will TikTok be a parallell arm or will it help Microsoft's consumer tech ambitions for One Drive, Xbox etc?