The story that I've heard is that people are staying home, and not going out and buying stuff, in retail stores.
The ones that are going out and buying, are using plastic, because cash is, you know, "germy".
People are not tendering coins, so there are none from that source to be used as change.
On top of that, the mint is supposedly shut down, or very limited, due to COVID.
Sounds reasonable to me. (Baaaaah!)
Sorry. Not buying the conspiracy theories.