Too many parents are betas or afraid of the kids calling the cops if they spank them. I warned mine early that if they ever did that to me, they’d be out of the house and in foster homes as soon as I got back. Never had a problem after that, or much of a need to spank for that matter.
Show them pictures what foster homes are like. Call their bluff. 99% of the time, it won't be an issue. Like you said, this generation of parents are betas.