There were competitors, but none of them were overwhelmingly better. Each had advantages and disadvantages. In the end, Biden was the consensus, as a combinatio

There were competitors, but none of them were overwhelmingly better. Each had advantages and disadvantages. In the end, Biden was the consensus, as a combination of experience and overall favorability. If Biden had declined to run, you would have seen most of them again for primaries this year. It's hard to know who would have won. Most of the candidates that thrilled some people were deeply disliked by others. It's rare to find a candidate who thrills everybody in the party. Barack Obama managed it, at least for his first term, where nobody really knew him and were able to project anything they wanted. The interesting part is that Trump thrills only part of his party, while being deeply detested by others. They do, nonetheless, turn out to vote for him.