By contracting out, you get people who hire workers willing to do work for the least amount of pay, unlike union workers who get better pay and tend to have formalized processes that do the work right the first time, even if it seems over done.
You don't know how business works if you think contracting out has anything to do with 'good' work.
I live in a city that contracts out everything but the most emergency of repairs for sewer work, the private contractors take longer and leave the areas they work in fucked up every-single-time. We have a mile of road that was ripped up and repiped by contractors, after it was done the road was littered with dips and potholes and they are having to completely dig up and repave the entire road now as a result. Contracting is about making money off government and doing it as cheaply as possible.