I though people voted him because they had lost their jobs and he will bring them back.
I think unemployed vote were marginal, point was that bringing jobs back ofcourse affects middle class and business associated with big companies. eg if you start manufacturing cars, someone have to repair them as well, someone have to insure them, someone have to transport them around etc etc. thats what is creating jobs and benefiting middle class
But if everybody already has job, why they would need drastic measures to create more of them? Do they plan to bring Mexicans to do the jobs or what?
Also car manufacturing don't itself bring repair jobs you need people buying said cars and use them to make repair jobs, and bringing manufacturing job to back to US may rise prices of cars, as manufacturing in US is said to be more expensive than it is in Mexico, and higher priced cars usually mean less sold cars, which means less need for repair shops etc. which means less jobs in that sector.
If there are more jobs than people, it drives companies to compete for employees -> salary raise -> happy middle class
so yes, it can drive price of item in question higher, however you gain more cash as well, and not all items will go up in price or not that much as your salary (in theory at least)