Fixed price for drinks

Not a barista here, but I’m curious to get insights from professionals.

I’ve been traveling quite a bit through Europe and noticed that most places have fixed prices for their drinks, rarely adjusting them based on the coffee you choose. This is especially true for pour-overs, where you can usually select from whatever beans they have available but the price remains the same whatever coffee you choose.

I understand the idea of keeping it simple, but since the most expensive ingredient is the coffee itself, why not price it accordingly? I’ve only come across a couple of places that do have a coffee menu—similar to a wine menu—where you pick your beans, and the prices vary depending on your choice.

So, I’m wondering why this practice isn’t more widespread?

Thanks!