Don’t think we can get rid of unions but we can certainly lower taxes and regulations. That said, you can’t require US production to have required massive labor, environmental and other regulatory costs and then allow MNCs to skirt every last law by building 20 miles south of the border and import tariff free, especially since our goods that get sent there (and Europe/other places) get a VAT tax added there.
Just make all states right-to-work and remove compulsory union dues. That right there will gut most of the unions.
Car companies can build their plants in the southern right to work states and avoid unions.