I agree the coffee at starbucks isn't great, but I feel the coffee at dunkin and mcdonalds are both better than starbucks. I like black coffee though, and Starbucks drip or americano just isn't good - I see starbucks more as a desert place than a coffee place, and judged on that they're good. I think more people want sweet milky coffees, and that's fine. That plus the environment is a big pull of Starbucks. It's not my thing, but I get why people like it

EDIT Also, I'm pretty sure the better coffee at mcdonalds happened after starbucks, IIRC they put a lot of effort into improving their offering after starbucks exploded

The SB blonde roast is a lot better than Dunkin or McDonalds, in my opinion.

The Starbucks near me doesn't even brew coffee any more. They switched to these automatic machines that "brew" a cup in about 15 seconds (ie. vending machine quality). Its undrinkable now. In future would only order espresso drinks or cold brew.