Interesting read. I can see the mobile mechanic taking off in more densely populated areas. I have a few friends that have tried it in my area, and the work is inconsistent. Working in a shop myself though, I can attest to the fact that bike sales are flat, and online ordering is a huge piece of the pie.
I don't think walmart is as big of a threat as Amazon and bikes direct type sites. (bike sales wise) Repairs are a different ballpark