When I was photographing Toronto fans on the city streets just a couple hours after the Raptors won the championship, there were people already selling "2019 NBA Champions" merchandise and people already wearing 2019 NBA Champions t-shirts. Obviously none of this was authentic.
The miracle of the Internet means anyone can steal images and logos and then produce t-shirts, posters, etc.
Is anyone selling reprints of the news articles about the series? Any large posters filled with text? Or are still photos, and not video, the most popular and memorable? And yet newspapers still fail to see this, even online.
The merchandising of sports is both interesting and somewhat disgusting. Sports events learned a long time ago that fans will buy anything with their team's logo on it. It's a huge bu$ine$$.
Remember when sports teams had only two jerseys, one for home and one for away? Now some teams wear as many as six, or more, different jerseys. More jerseys => more sales.
Winning players *must* put on the championship hat and t-shirt at the end of the event. Many years ago it was optional, now they must do it. The players get photographed wearing the stuff which helps promote the merchandise. Watch carefully and you'll see that as soon as the championship game ends, one of the first people to run onto the court or field is the hat person.
At some events, if the sports event has lots of merchandise to sell, the winners have to rotate through the entire range of hats/tshirts. It's quite comical to watch: winners put on one hat, photographers click away. PR person makes players change hats, photographers click away again. Repeat, repeat, repeat.
Large sports merchandise manufacturers make the souvenir hats and t-shirts even before they know who will win. As soon as they know which two teams are in the finals, they start production of both versions of merchandise: one version if Team A wins and another version if Team B wins. Once the championship is over, the losing team's products are destroyed.
When I was your age, manufacturers would send both versions of their products to the newspaper many days before the final game (eg. Grey Cup, Super Bowl, Stanley Cup, World Series, and even some division finals). We'd photograph people wearing each version and wait to see which team won. Only photos showing the winning team's products were published. The agreement was that no picture could be published until after the final game, no merchandise could leave the building (it was kept locked up when not being photographed), and the losing team's merchandise had to be destroyed or returned to the manufacturer.
All of this is about making a quick buck. Strike while the iron is hot.