Your predicate is mistaken: Labor unions never have been, are not, and never will be a tool or model of political action.

Collective bargaining is an economic tool that, most often, functions as check to individual power/control in markets: that is to say they are a balance to an underlying push to exploit. In the US, the labor unions that have suceeded in embedding themselves appropriately in markets have done very very well for their members in those markets: specific instances are; police; fire; teachers; and all major league sports. Why does Tom Brady get membership in a union and Amazon warehouse workers do not?

The countries that have fully embraced unionization, Germany and Japan in particular, are very very strong economically.

Anyone wishing to 'move past' unions should spend a great deal of time and cognitive cycles on one question: why do the 1% hate unions to the extent that they have worked very very hard to make unions very very difficult to organize?? (see your own citation on contract work...)

A second question to ponder is why are corporations--a method of collective action (if not bargaining)--acceptable but unions are not?

(A third question to ponder might be why one would want to do the work of the 1%...?}