demand is there for MSRP but not so much above that. Most of the people who REALLY wanted to play BOTW on the switch got one at release, while there are a few who still want one there are very, very few who will pay $500+
I mean there are nearly 12k listings for it on eBay, a quick look shows ~20 selling an hour or ~400 a day (lot fewer sales in the off hours), which means it would take 30 days to simply exhaust the switch supply thats currently just on eBay, not to mention more going up all the time. A LOT are selling for $400-450 or so too, which after eBay fees and taxes is really just a $30-60 profit.
We also already have seen reports now that more switches are going to be available at gamestop on Mar 22, at Target and Walmart around that same time, and Nintendo is going to produce 16m switches in the next 12 months, up from original estimate of 8m (they have sold a little under 2m so far). So sure, there are definitely people who want it NOW and will pay whatever, but that pool of people is shrinking fast and will more or less be gone soon as switches start flooding the channels once manufacturing catches up.
There are only 2000 listings on EBay. You have to filter out everything but the consoles. Stock has been slowly dwindling over the past 10 days. It was over 10k. Also many listings have a quantity greater than 1 and the number of listings left on Ebay reflect not only the number sold but also the number of new listings added.
Even with more coming I think there will be a tight supply for the next few months. IF they are doubling production then it won't happen overnight. Stores probably won't get a ton of units in the next month. Mario Kart is coming late April, and even though it's just a port, many haven't played it and it's one of their most popular franchises. The Switch isn't the mainstream craze that the Wii was, but does have the advantage of being both a handheld and a console and sales seem likely to reflect that.
The Switch has steadily sold for $400ish on Ebay since launch so it's going for a decent amt over MSRP. But obviously $100 above isn't enough for resellers to make much money after fees and shipping. Prices have increased as supply has gotten really tight.