The point, in the UK at least, is that 40% of households don't have a cable or satellite provider - they use free to air TV. Which doesn't come with a DVR.
They are free to...but they don't.
I think the obvious conclusion is that people like DVR but aren't willing to pay outright for it. The vast majority of the ones in use are the ones provided by cable companies for little or no outright cost but subsidized by the monthly cable bills.