But their form is mostly irrelevant to their function. In order to signify your tournament as more important than other tournaments, the trophy needs to be more spectacular in some way. So the tendency is to make them either bigger or more garish. They need to look valuable without actually being valuable, or the winners wouldn't want to give it to the next winners.
I played for Lyn, the best team in Oslo, in the late 1960s. You would open the newspaper and see adverts: We have an apartment for rent, but not for people from the north.' You felt disgusted to see it.