It does exist in the US, and they do sell them at Wal-Mart, although not the full line and (at least in my area) not in-store. The Sceptre website shows everything 'ReStock Soon', so maybe the latter is temporary.
There aren't many reviews of the sets - Consumer Reports doesn't even track a single one right now - and what you can find is mostly mediocre to negative.
For a datapoint on Sceptre quality, I've got two 24" Sceptre monitors in front of me that are incredibly annoying because Sceptre cheaped out and doesn't bother to program the monitor serial number into the EDID and instead just use a static placeholder value. This means every time I reconnect my work machine there's a 50/50 chance the display layout will be backwards because MacOS can't seem to use the interface path to differentiate monitors like Linux does.
My experience has been mostly fine, although I also had some EDID challenges for awhile which I chalked up to my complicated setup. However I also don't mind things like backlight bleed.
They're not exceedingly rare. A tad more expensive, yes, but not hard to find.
The brand is called Sceptre, they sell them at Wal Mart.
Am I missing something? Maybe that brand doesn't exist in the US?