Unskilled laborers can not successfully strike. Walmart will just fire them all and hire the next group of teenage mothers that walk in.
If they time it well they might. It requires at least some knowledge about how to run a cash register so a strike around a major shopping day (Blakc Friday) would have a noticeable effect on Walmart's profits on that week/weekend.
That said - they didn't time this well.
I hope every walmart shuts down forever.
I think the loss of 1.4 million jobs and the second largest company in the world closing down might have a slightly noticeable effect on the economy