To add to all this, if most of your customers are seriously there to taste their flavored syrups and milk of their favorite drink, you wouldn’t want to alter or even ruin that with unexpected, unique coffee flavors.

I know an adult care nurse, she told me “everyone wipes their ass differently and they’re all convinced their way is the only way.”

Dark Roasted coffee is the only way Starbucks can be Starbucks.

Lighter-roasted coffee emphasizes origin flavors and i agree with you --generally tastes better and is more interesting.

But you can’t sell coffee like that in tens of thousands of coffee shops and have it remotely consistent.

Coffee growing from the same plot but on one side of a hill will taste different from the other side due to getting different quantities of sunlight. Complex origin flavors will always be the domain of small specialty coffee shops.

Starbucks has McDonalds-like consistency serving millions of customers a day and that’s only because they emphasize the flavors they can get consistently–roast flavors.

TL;DR The bigger the chain, the darker you have to roast. That’s just how coffee works.