Specs aside, history has proven time and again that a base SKU cannot exceed $399 and achieve widespread adoption. I suppose if both Sony and MS launched at $499, it would be interesting to see how that played out. But, if one of them is at $399, and the other at $499, I suspect the $399 will win handily. We've seen it over and over again.
And, yes, inflation..... But, inflation in video games has not been a thing.