I'm just wondering here: Might it be hard to find a mechanic like this in February in Minneapolis?
This is the same thought that came to my head. Weather conditions would certainly cause a problem. Heat, rain, snow. How could a mechanic come to your office and do work on your car 2/3 of the year? the conditions won't permit it. I suppose if everyone lived in San Diego, CA things would work out great though. I suppose that the mechanic could come pick up your car at work and drive it to their garage/shelter - then…
Alternatly some mechanics offer courtesy cars, so you can stay on the road while your car is being fixed.