It should be pointed out that VMware started as a tiny, scrappy company mostly focused on selling workstation seats for you to run Windows on your Linux computer (which I did back circa 1999, so I could use Linux on my desktop), and VirtualBox started out from InnoTek, a tiny company which was essentially making software to emulate Windows on OS/2, and then later did a contract with Connectix to run OS/2 on Windows (or other hosts) using Virtual PC.
replyConnectix got bought by Windows, and InnoTek got bought by Sun, which is now Oracle. Connectix themselves started as a scrappy outfit making it possible to run DOS/Win95 on a Mac.
The core emulation was pretty much done and stable and optimised before the billion-dollar corps bought them out.
vmware apparently had 20 employees in year one, I don't think a single person has ever worked full time on a mac emulator (other than Apple's internal ones, of course)
replyeven a "tiny, scrappy company" has massive manpower compared to 99.999% of open source projects