https://www.gamespot.com/articles/snes-classic-edition-pre-order-guide-nintendo-expa/1100-6451207/

September 12: While pre-orders themselves may not be any easier to get, Nintendo has provided some encouraging news for those hoping to purchase an SNES Classic Edition. Nintendo of America president Reggie Fils-Aime recently implored people not to pay more than regular price for the console. Now, the company has announced that the SNES Classic will continue to be sold into 2018, and not just in 2017 as previously planned. (The NES Classic is also coming back.) On launch day in the US specifically, Nintendo said that "more units of Super NES Classic Edition will ship ... than were shipped of NES Classic Edition all last year, with subsequent shipments arriving in stores regularly." This is still no guarantee that you'll easily get one, but things are looking better now than they did.

August 31: Walmart has begun contacting certain customers to notify them of canceled SNES Classic pre-orders. Based on reports from NeoGAF and Reddit, this only appears to affect those who ordered more than one unit, and it seems only the additional orders have been canceled. (We at GameSpot have also received such a cancelation notice, reducing an order for two units down to one.) There's no official word on this yet, but it's possible this move could free up additional units for pre-order.