They will need to work with manufacturers to provide and monetize 3D printable files for consumer goods. Basically what Apple did in the music industry.

I work for a 3D printing firm and 3D printing is already disrupting the retail space. I think most people would be surprised at how 3D printing is being implemented and who is using it. We've printed parts for large companies and individuals. I've seen individuals save $1000s and one company in particular save tens of millions of dollars because of 3D printing. It will just continue to grow.

Walmart should take note, Amazon, their biggest threat, is already selling 3D-printed objects. Here's a link to their store.