Why is it everytime SF3 sales are brought up , people default to Dreamcast-blaming. Sorry but no. SF 3 NG/2I were a failure not just on consoles but also arcades. 3S was an amazing solid title but failed to gain traction.
Yes agreed the port situtation is pretty bad compared to the rest of SF titles. But even in that niche hardcore audience the dreamcast had , it couldnt match up to CvS,MvC,SFA3 and even Guilty Gear.
^^ Japanese sales numbers.
Most Alpha games would have possibly crossed 1m.
But they are all spread apart on Different SKUs. PS1,DC,Saturn. The PS1 version of Alpha 3 is the only SKU to have crossed 1m units. Alpha 2 was 900k on PS1/Sat in Japan alone , And Alpha 2 also had different publisher for the US/EU so they dont technically come under Capcoms financial reports.
And yes it had much better porting , but that is mostly due to how easy it is to port CPS2 compared to CPS3.