As a brewer, when you use local ingredients you quickly learn it’s not bollocks. My local malt (which I don’t particularly care for) has a very specific flavor profile and color.
As an even more basic example, go hunt down some New Zealand Cascade hops, or have a beer brewed with NZ Cascade. It is not the Cascade you are familiar with. Terroir absolutely does play a factor. It’s why Nelson (now that it is “open source”) grown anywhere else will not taste the same.
This is something I’ve thought a lot about. I love going to vineyards and tasting the wine from grapes grown onsite. It is a kind of intimate thing to “taste the dirt” where people work as live.
Beer, on the other hand, doesn’t really have this same quality. Grain and hops are shipped all over the place, and most places have access to whatever they need. That said, I do think there is a kind of cultural terroir many places. You have Kölsch in Cologne, you have IPA in San Diego, you have a bitter in London. Even though you could make these anywhere, there is still something to tasting the local tradition.