If the gunmakers would take a stand, this would end overnight.
Simply refuse to service or sell to any governmental agencies in states where such draconian laws are passed, ala Ronnie Barrett in California.
If manufacturers are currently enjoying record sales, now would be the time to do it to minimize the damage to their bottom line as much as possible.
If the local SWAT teams can’t get the shiniest new toys, they’d turn up the pressure on their legislatures to do something.
What makes you think they wouldn't just exempt themselves from the law, the same way they do with most other laws?