At least one computer in every US household (these stats show 2 but let's just keep it one https://www.statista.com/statistics/1107206/average-number-of-connected-devices-us-house/ since it is an average). It's hard to say that desktops are mostly used in business since there are only 754,633 office workers in the US (https://www.zippia.com/office-worker-jobs/demographics/) and 131.43 million households. ( https://www.statista.com/statistics/183635/number-of-households-in-the-us/ )
Also, many people used Windows XP after its EoL, so much so that they increased it. It's likely going to be the case here. Windows 10 EoL doesn't mean the end of use. People seriously, care little about security. They don't care about having the latest updates. They care about using a functioning computer.