Are there laws protecting unions? Technically, yes. But as we have learned in recent years, and since the book “Confessions of a Union Buster”, we know the larger firms where workers really want to unionize are prepared to stop unionizing campaigns in their tracks and hire some of the biggest union busting firms to do so. Workers have been persecuted or fired by the boss for trying to unionize, and employers do not face legal consequences for this. Even after the union wins an election, the boss can single out union employees and fire them ultimately again without consequences. Amazon trains their management to look out for potential unionizing activity.
Also, the private sector used to be much more unionized, but it has been reduced by half since Reagan fired the striking Air Traffic Controllers. In the 90s a majority of US factories threatened to fire their workers or close the shop if they attempted to unionize. Reagan and the Republicans strengthened the employers against unions. Republicans in recent years have been continuing the neoliberal agenda to empower the corporate class, passing ALEC inspired legislation in their respective states to attack unions and create an environment more suitable for the employing class (which has not reversed the trend of closing manufacturing plants and shipping jobs overseas).
I think you are exaggerating the generosity of government job remuneration. There is a labor shortage in the public sector too, especially with Department of Corrections jobs (at least where I live). They are working 16 hour shifts currently.
The problem with being given the “wage you earn” is that capitalists never return to you the full value you produce for them. You will always be provided a substandard wage (even while they are enjoying record profits, like now). Wages have gone down over time but prices have gone up (and productivity has gone up too, where’s that pay increase?) And as you just demonstrated, unions help increase wages for the working class.
There is some truth in the averageness and unhelpfulness of a typical business union. They surrender power to the boss and make concessions too often. I’m a member of the Industrial Workers of the World, my monthly dues are just $11 and I’m happy to know that my money is going toward other unionizing campaigns, giving money to our prisoners union so they can be setup with a life on the outside or fight for their rights while they’re on the inside.