Counter-argument:
Why the rush for so many to declare candidacy a year and a half before the election?
Especially for candidates with name recognition.
Like Biden needed to announce this early to build up his profile.
If anything, it would normally make more sense to stay under the radar and let your primary opponents beat each other up for a while.
Unless they were using the candidacy as a shield against some sort of anticipated legal trouble…
Naw, they wouldn't do that, would they?