We know Biden chose to run in order to stop Trump and he succeeded. However this doesn’t let Biden off the hook, people chose him as an anti-Trump choice but not necessarily because Biden was the best choice. For example, Biden has shown signs of disorientation that became noticeable in speeches, interviews, and debates during the campaign. While a change in leadership was deemed necessary by voters, objective observers are concerned. In other words, voters saw this election as a necessary agent for change, but are concerned Biden is not the leader we need. The agent for change may well be Vice President-elect Kamala Harris.
Kamala was a long-time adversary of Biden but suddenly became an ally saying nothing but flattering things. It’s pretty simple that Kamala’s change in tone happened when she realized that as his running-mate she could influence policy. People who were reluctant or hesitant to support a Biden presidency changed their view embracing him despite him not being the Democrat's first choice for Commander-In-Chief. What we're left with is an administration that was created out of compromise. Some leading Dem’s didn’t want him in the Oval Office but are willing to make that compromise in order to get policies and ideas pushed that he would accept and pass with the influence of Kamala Harris.
Time will tell whether Kamala's influence is the engine for change that is desired by the country, but indications are that she will have a strong role. That strong role could catapult her to be the front-runner for the presidency in 2024.