Ramjet007:
They could up the min spend from $20 to $40 or $80
That would certainly help to make it more viable, but even at that level they'd likely make a loss on a fair proportion of the sales, especially with items that are bulky.
I guess it depends how desperate they are to push sales volumes.
I know with my own business that it's becoming increasingly difficult at the moment with significantly higher shipping costs (along with all the other elevated costs).