To recoup your R&D costs and make a profit, you decide that you're going to sell these pumps for $100. Those in the market for a 1,000 hour pump think that's a fair price, but those who only need a 100 hour pump think that that's outrageously expensive.
If you bring the price down to make the 100 hour pump people happy, you're cutting into your margins for the 1,000 hour people. So you segment your market: $100 for a 1,000 hour pump, $40 for a 100 hour pump. Your 1,000 customers continue buying the pump at the price they've always been paying, and some of the 100 hour people start buying at $40. That incremental revenue is all gravy; you didn't have to sink R&D money into a second product (other than building the DRM)