I like this for two reasons.
First, it gives you a different spin on Herbert Spencer than is typical. He was not an advocate of the dog eat world he is associated with.
Second, it explores reason for unions, but does see higher wages across the board as part of that reason.
The latter seems important to me, because it is pretty hard I think to support a claim of unions raising wages for some workers without decreasing them for others.
I think unions should focus on fosters programs such as effective training to allow workers to transition to new jobs even as existing jobs disappear in inevitable ‘creative destruction’.