Does this just ban importing DJI products (bad enough) or does it also ban owning and/or flying a DJI drone you already own? (really bad if that's the case, but also would be difficult to enforce)
If they do revoke the existing Equipment Authorizations, then the drones become illegal RF transmitters and wouldn't be legal to fly, although enforcement would border on impossible.
Since the software phones home it most likely won't work anymore once the ban is in effect.