Huh? The steam hardware survey is sent out to a indeterminate number of people each month. The results of the survey are compared to the previous month. With 125M active users the sample size doesn't even have to be that large for a 95% confidence rating. Developers then use that data to make decisions about the games they are building - not ones already sold. They can sit there with reasonable accuracy and say "The vast majority of steam users have less than 4 cores, thus we shouldn't make a game that absolutely requires 4 cores for an enjoyable experience" or "The vast majority of steam gamers are using 1080p and below" or "The vast majority of steam gamers have a 1060/480 or weaker". You don't need high levels of confidence in order to draw those conclusions and those are the conclusions valve designed it for.