Sure you have a point, but it's also true that people buy what their friends buy.
This was a major selling point of 360 as well. People weren't buying ps3's because their friends all had xboxes, so they bought xboxes.
Their friends had xboxes because xbox released almost a full year earlier.
Now, in this gen, xbox is looking at almost a year delay in countries other than the 13. To me it looks like Sony is trying to cement every country that isn't USA or Brazil.
So yeah, having enough stock is important, but it's also important to get that head-start.
Hard to say which one is more important.