I’m not sure if we can call “pizza with toppings other than the strictly Italian defaults” as “trendy” anymore. Most Swedish pizzerias will happily make you a banana curry pizza, and it’ll be the one of the standard topping options on the menu. Is it a trend if it’s normal?
I think we (humans) have been putting different things on bread for as long as we’ve had bread, like GP said.
Once upon a time (only about 500 years ago), tomato was a new exotic ingredient in Italy too.
So exotic they called it "the gold fruit", "pomo d'oro" - gold being the seeds inside.