5th edition is not around the Corner.
Here is the bigger question - what if WoTC released 5e and nobody cared? If you are a 3.x/Patherfinder person, you are already covered. 4e is not getting any love right now anyway, so would they miss WoTC not putting anything out for them?
Under 3, you have pretty close to a building block method for a PC to kill an Orc. Under 4e, you have great teamwork methods for the team to kill an orc. If you are into random dice to do things, pre-3e is the way to kill that orc. Is there going to be an new an interesting way to kill an orc in 5e that is going to pull people in to play it?
For me personally, Eberron is what kept me buying books during the latter days of 3e. I would pick up the occassional "Complete Commoner" along the way. But without new content, I would not have been a buyer in the later years of the cycle.
Since WotC does not want to produce modules and is only doing a couple of books per setting, that translates into few new ideas. I am a lapsed D&D player at the moment and asked in a thread about 2 months ago is their anything interesting I should pick up from 4e for cool ideas (non-player crunch) - pretty much crickets if you already have 3ed stuff (there is some stuff if you are new to D&D).
That is their issue - 3e and 4e are "too good" mechanically - the edition treadmill just will not work. If they want the sales under any edition they need some fresh ideas, not more orc-slaying methods.
Anymore, D&D is like Microsoft Office -- does anyone get excited about an new version of the suite? Its still Excel, Word, PPT and some fringe products. If a new computers come with the update, then fine, I'll use it - but the old suite works just fine. If I wind up in a group that plays version X of D&D, I'll play it as it is still rolling a d20, killing critters and taking their stuff.