I disagree.
I had a cheap cruise in March. The food in the buffet was terrible. Service was slow because of understaffing. I don't care about bacon, I do order it in the MDR though.
I recently sailed with another company with a friend on a really good deal Some things were better, some things weren't. There was always bacon at the buffet. Their buffet was far better than Carnival.
Would I sail them again? If the price was comparable to Carnival. But I did not find anything that I found worth paying significantly more for. I love food. But I can always find something to eat on Carnival so it isn't a dealbreaker for me.
I have looked at other lines but for the price, I get to be somewhere warm, visit different places and have an overall enjoyable experience for a lot less than other lines so as long as I am getting good prices, I'll stay with Carnival. When the day comes that I'm paying the same for a Carnival cruise as I am for another, I may move on.
I use the money I save to enjoy more on my trip in other ways. And more trips.