We should take a look at the data. (Link at end of post)
Generally, between 1996-2016 (inclusive), the Asian and Hispanic rates of voting participation have been steady at just under 50%. There are no massive swings.
That leaves us with one materially significant minority voting group - African Americans. If you discount the Obama years (2008 and 2012), the AA vote is essentially UNCHANGED since 1992 (at about 60%), with only 1996 seeing a dip. In other words, the % of AA who voted for Hillary Clinton was exactly in line with non-Obama years.
I find it hard to believe that Biden will result in a higher-than-Hillary AA voting participation rate. ESPECIALLY since it is AA women who make up the bulk of the AA vote (AA men vote at very low rates for a host of reasons). And AA women voted for Hillary at >90%. Biden would probably not even get her #s, but even if he did, there simply exists no historical data suggesting that aside from Barack Obama, the AA vote swings wildly based on the candidate.
A greater % of AA voters showed up when John Kerry was running against GWB than when Hillary squared off against Trump. I think it's just a totally invented narrative that Biden is the only one that can get out the minority vote. The historical facts simply do not bear that out at all.
https://www.pewresearch.org/fact-ta...as-a-record-number-of-americans-cast-ballots/