The 360 gen had series S alternative model as well. The core one (named arcade later on). At launch there were to models, the pro - 399$ and the core one - 299$. 2007 they released the elite one - 499$. So It is the same. The Elite one counts as the X one - 499$ and the core/arcade counts as the S now - 299$. It's the same.
However now we have shortages, and back then there were no shortages. And even with that XBSX makes way more sales for now than the 360.
If we have to remove the sales of the S model from the graph then we should remove the sales of the 299$ core model of 360 too.
Exactly. The 360 had its own advantages and visa-versa. Saying something is unfair is a strange way to discredit another systems success.