I have literally seen this happen to my local dollar general with Cheese-Its Extra Toasted. They used to never stock them. I randomly caught a hankering for them after trying them out.

They went from only ever having maybe 5 boxes on the shelf to having it 3 rows of 5 deep after a month.

After 3 months I lost the hankering. Still get me a box every now and then though. They still keep that shelf filled.