That's the fallacy being perpetuated, that non-union workers aren't as well off as union members. In most instances, the benefits are on par, if not better then what union facilities offer, because they are trying to prevent the unionization of the facility and doing so as a preventative measure.
“In a November 18, 2008, New York Times editorial, Andrew Ross Sorkin claimed that the average UAW worker was paid $70 per hour, including health and pension costs, while Toyota workers in the US receive $10 to $20 less.[17]"
Furthermore, the foreign makes did not have to deal with the job bank, where workers were paid 95% of their pay to do nothing. This practice has ended, due to the near demise of their employers for indulging in such insane largess.
Since 2007 things have changed a bit. “According to the 2007 GM Annual Report, typical autoworkers earn a base wage of approximately $28 per hour (higher than the average university educated engineer). Following the 2007 National Agreement, the base starting wage was lowered to about $15 per hour.[19] A second-tier wage of $14.50 an hour, which applies only to newly-hired workers, is lower than the average wage in nonunion auto companies in the Deep South.[20]”
This does not even begin to address the restrictive work rules, slowdowns, and other inefficiencies that are guaranteed to be manifested in any union shop. Bottom line is that the imports are nuts if they allow unions to get a toe hold in their factories.