I mean that as of 4 months ago, Sony and Microsoft would have had a pretty good idea of demand. Changing production lines takes time but if we reach a point where every store is full of series s but every other system is sold out, Microsoft is losing a ton of potential money. I think either they expected Series S to sell way more, or other systems will slowly start catching up too.There are way more factors at play than supply and demand for their own systems.
Demand doesn't matter too much imo, as long as it was predicted and stays consistent. PS5 has higher demand so they'd be wanting to pay for more production, while Series X has lower demand so they'd be paying for less.
MS could benefit from making more systems, if people get tired of waiting for a PS5, they might figure that some of them will buy a XSX.
Another factor is the supply of chips, it is probably less than the demand of either.
There are a lot of logistic factors at play, and a lot of short term and long term planning factors that we don't even know about.