Low-end wages are affected by automation, globalization and immigration. In that order, I believe. To his credit, Trump is trying to tackle the last two.

If you provide unskilled services (e.g cleaning) then unskilled immigration is very bad for your income. I don't think any reasonable economist would object to that.

The "job pool" does expand over time to match the labor pool, but if immigrants don't have the same skill profile as "the natives", then some of the natives are gonna lose.