I type this as someone who is a not a 5E fan (I prefer 4E or 13th Age) but looking at 5E as objectively as possible, I think (IMO/YMMV) that WotC is basically a skinny Paizo. The product line is skinnier. The rules are skinnier. The staff numbers are skinnier. But at the heart of of both businesses are their twice-yearly adventure paths. It's just that WotC is producing their "adventure paths" for a lower cost.
Paizo seems to be making money so, presumably, a lower cost version of Paizo is making money too. Until the Paizo model fails, I don't think 5E is going to fail unless they produce an adventure path as bad as the two they squeezed out through clenched cheeks in 4E.
Also, I can imagine this Paizo-lite strategy was an easy sell within WotC: "Let's be like Paizo but with lower costs while we wait for a windfall gain from the IP."