Plant them! They don't need to be pre-sprouted.
As noted, perhaps super market potatoes have been treated so they don't sprout.
Best to get some to plant that have not been treated. Though if super market potatoes have got sprouts coming of course they will grow.
I don't like to plant super market potatoes for disease reasons. I prefer to get some certified seed from a nursery if I am buying seed potatoes. Most years I plant potatoes from last season that I have kept in a pit over winter. Since it is vegetative reproduction the genetics remain the same from year to year.