It's easy to attract a large segment of the market over to your, near clone, of that product for less. You don't even have to make it in China - you're one guy with some outsourcers that'll do everything for you - you can just lower your margins. The problem now becomes that you need to sustain that business. You're not making enough margin to hire a handful of additional engineers to design the next generation products while you sell today's. You're making a comfortable living for you - while driving the innovator you just copied to lower their margins and lay off staff. (Or, exit the market entirely.)
Copycats of OSHW at cheaper prices who don't innovate new capabilities harm the market in the long run, but make today's customer happy. It drives OSHW vendors out of the market, and forces new players to make a choice between open-sourcing and facing massive margin pressure, or come out closed-source and ensure they have enough breathing room. Of course, it's a false dichotomy: we've been copied several times, but focus on extreme customer service, and way out of our way warranties to differentiate ourselves, while also continuing to invest in new products. But, we're also in a much smaller niche.
That being said: I haven't followed Makerbot in a while - how much new R&D do they do? That is, have they been coming out with systems with newer capabilities and competing aggressively, or have they largely been resting on their laurels?