T-shirts are made for both the Super Bowl winner and loser in advance so they can be sold as soon as the game is over. The gear is sent to other countries. Manufacturers are not allowed to sell them in the US even though they would be collector’s items. Here’s a picture of people wearing shirts after the undefeated 2007 Patriots lost the Super Bowl. I don’t know where it came from.
Remember when the Buffalo Bills lost four Super Bowls in a row? Someone said “In the third world, they must think the Bills are awesome!”
What Happens to the Losing Team’s Pre-Printed Championship Shirts?
What happens to Super Bowl T-shirts, other merch for the losing team?