delericho
Legend
The fact that there was this "WHAM! Change after change" effect should demonstrate the obvious: 4e was NOT doing well. If it had been selling a ton of books, they would have changed nothing.
I think it's not as simple as it being a success or being a failure. It may well have been successful, and indeed selling a ton of books, and still not been doing well enough to satisfy the needs of Hasbro. Especially if they sank a whole bunch of money into developing the DDI and it just hasn't brought in the return on investment that the team promised management when they sought the green light for it.
Bear in mind that what would qualify as an awesome success for any other RPG company (including Paizo) may well be considered an Epic Fail by Hasbro. (Indeed, do I not recall an anecdote from just after the takeover, when the WotC guys were congratulating themselves that the brand-new "Psionics Handbook" for 3.0e had sold lot of copies, only to have the Hasbro rep ask, "Why are we even producing this book?"?)
2-4 3d4 horned devils appear, playing "Highway to Hell" with an assortment of cowbells
Do they threaten to eat your soul unless you play for them the greatest rock song ever?