Why is McDonald’s so popular?

I recently visited a McDonald’s on my way home from a night out. I’ve never had such bland tasteless fast food.

It’s probably been 20 years since I’d last been to one, though I have partaken in a Burger King now and then which tastes way better.

It got me thinking. And aside from the fact both are empty calorie junk food and really bad for you. Why is McDonald’s far more popular than Burger King when Burger King actually tastes of something and has actual salad in it?