There are (non-trivial) ways of making back-up copies of your purchased digital material, just as there were for Blu-Ray and DVD purchases in the past; so the choice isn't solely between piracy and purchasing.
It's easier with books, or music (with different degrees of truth, a single singer-songwriter would be a lot easier to pay directly than a symphonic orchestra...), but involved products are not easy to finance individually - or pay individually - that's the exact reason right-management studios exist to begin with.