Biden 1988 and Biden 2020

Joe Biden wanted the Democratic nomination for president in 1988 (hoping to run against Bush 41).  He was forced out of the race when the media noticed he had plagiarized a speech by Neil Kinnock--and that he had a history of "resume enhancement," claiming honors and experiences he never had. 

Here's a news clip from 1988. 

Here's a recent clip of Biden similarly enhancing his resume.  Why do you suppose Biden had to drop out in 1988, while, in 2020,  he won the election and, for much of 2024,  it looked like he a fair chance to be reelected?  Why wasn't Joe Biden the president we deserved in 1988, and why was he the president we deserved in 2020?