By your logic, games would only target 1080p as that is the lion's share of steam users.All accurate, but also pretty much non-responsive to what I said. While Steam's measurement of ~9.2% may not be exact for every PC that has played a game in August, there's also no reason to believe the exact answer is materially different. IF the actual answer was double --- an incredibly unlikely proposition, the error is more likely a couple points at most -- would it still change the fact the publisher is aiming at a tiny fraction of existing PCs and therefore likely blowing it financially?
And yes, everyone knows you can try to play below recommended specs, just like everyone knows that is code for you will experience stutter, bugs, and an overall unfun experience. The only likely mainstream response is to choose another game.
And further yes, I expect the Steam surveys from next year and the year after to look different. That will not help Serious Sam's publisher with this title, it will be on the deep discount rack by then.
Still, like I said, if their business plan was entirely focused on the consoles they could still be fine. They may even clear some small additional profit on the PC port. It's just they are certainly not going to sustain a development budget on a title that works well on only 10% or less of existing PCs at time of launch.
It also overlooks the fact that people with more money for hardware also have more money for software.