Most versions of the RepRap plastic parts are designed specifically to be reasonably easy to print on any 3D printer with an adequate build volume, without support material. Some kits involve some parts that are too large for the build volume of a Replicator Mini (power supply cover being one of them) and many involve several parts big enough that they would have to be printed one at a time if using a Mini, but if you have the patience (and either something bigger than a Replicator Mini, another way to get/make a power supply cover, or a kit design that doesn't require a power supply cover), I don't see anything that would keep you from making RepRap plastics kits on a MakerBot.
As for the article's premise, the article is almost five years old now and the market is now saturated. The printer itself is becoming a fairly low barrier to entry and this is a pretty obvious way to recoup some of the investment. If you want to sell successfully now, you would likely need to differentiate your products somehow, such as improved design, atypical materials that are demonstrably better (especially high-temperature materials that restrict the number of printers that could make comparable parts), or multicolor.
