Can't handle it? More can't conceive it by the correlation made here. Even if the supply constrain argument is correct, it in no way correlates to higher demand of series x. Even if there is higher supply of it, there's a limit of how many hardcore gamers will buy the console on launch. So even if they manage to make 10m consoles dosent mean that there are 10m people waiting to buy them. 

Could also mean that nobody saw this pandemic coming or the effect it would have with some sufering and some surprisingly benefiting from it like gaming did. 

As far as we know ms never made any adjustments to supply in a while and the higher demand burned the reserved stock but retailers dint order more because they dint know when this boom was gona end. Considering the one s is not gona be discontinued, this is likely as it always has been the one sold most as nobody will buy a one x when it will be obsolete in a few months.

Either way it in no way indicates any level of enthusiam for another product, wich may not be sufering from this pandemic by then. 

I can buy the theory that its supply contrained.

That would more likely mean slower momentum and brand awareness.
The factory isn't from MS for it to need a trade-off on production, they have a contract for X1 and now have a contract to Series X and lowering one doesn't increase the other. I would say it more likely makes the cost of each unit higher for the new unit since they have less volume contracted.
The ammount of stuff manufactured for smarphones and Switch limits the Series X production much more than whatever quantity they were making for X1.

Eh idk. MS has to do a lot to fix the hole left by Halos delay.