There are many opportunities to start the your own invisible company. I once started a small business ($33k/year) that sold exactly one product to one company for a few years. One thing the article glosses over in the Steven Ross discussion is that this guy was clearly entrepreneurial: he was able to see the gaps and find or build solutions to fill them. You can in fact build a business around solving a "simple" problem for one business, and because it is a small scale you are essentially invisible to the would-be competition.