Yes, but that's not a 1-man job. And that company is EXTREMELY smart.

It may sound stupid to compete with yourself, but what about 'owning' a google search term? Good SEO on all 3 sites may result in 3 top 10 rankings for a single product, 1 on each site.

If you owned position 1, 2 and 3 - what % of that search traffic do you think you would get?