Ok, but they bought DOS. They bought MSSQL (Sybase). They stole half of OS/2 and then pivoted to Windows NT with ex DEC folks. Its biggest products were all (mostly) bought. Oh yeah, Halo.
You're cherry picking. They built Windows. They built Office. They built Azure. Windows Phone (RIP). Exchange. Sharepoint. Visual Studio. Bing.
Every big company has a raft of acquisitions in their history and if you really want to you can draw a tenuous line between an acquisition and a subsequent product line. The claim that Microsoft "fundamentally doesn't make anything, they never have" is just silly.