It's true that Trump had a simple majority of votes, but you can win the electoral college and lose the popular vote; this is typically what happens for Republican victories. Kamala lost MI, PA, and WI by 3% or less. If those had flipped, she would have had her 270. You are right that third party votes wouldn't have been enough though. The bigger problem was reduced turnout from people not voting at all.
The fact that Republicans also managed to do so well in Congress to me suggests that the problem for Democrats wasn't really just their choice for presidential candidate. Voters really care about immigration and inflation right now, and those tend to be stronger for Republicans.
The obvious answer is that it's fast, tasty, and requires minimal effort for the consumer, especially if it's getting delivered. But it also tends to be very cheap compared to dining out. I don't know what you are ordering where a combo is so much but I normally get a bunch of food from Taco Bell to eat over the course of two days. I can get 2000 calories of food I like to eat for $12.