I would disagree with this.
There has been one overwhelming truth we have seen these past four years here on the EN World boards. A very large number of players who were pissed off about what was done to make 4E and who ended staying with 3.5 or moved to PF... always had a laundry list of things they shared with us that "had to happen" with D&D to make them switch back.
That told us all we needed to know. Most of them wanted to play 'D&D' but couldn't because of all the problems they had with the 4E system. But given the chance, they'd come running back once WotC got the system in order. The brand holds that much sway over us. 'D&D' is preferable over 'Pathfinder' for a good number of those players, if both games are comparable enough to get the gaming experience out of it that they want.
Never underestimate the power of the brand.
Certainly disagree. Where there's opinion there's tons of options for truth.
I'll reply with the following and leave things at this:
1. The brand was not powerful enough to keep their entire customer base happy when the product changed. This alone speaks to the close correlation between product and brand. I would never underestimate the power of the phrase D&D over the phrase Pathfinder, but the fact that there's discontent in the first place and lowered sales means that the brand can't overcome silly management based on its own merit.
2. What the brand needs is a strong product whose IP is protected. Time and time again, with good product and good marketing in place we've seen successful outcomes. You can't build future success by going backwards. Sometimes you just have to own your mistakes, take inventory of what you have and forge ahead. In my opinion, this is what Hasbro needs to do. If they must make a fifth edition, they're in a stronger position with their existing 4th edition product than they are if they dilute it with older concepts.
3. Last, I'd be careful not to directly correlate vocal complaining about 4th edition with sales of 5th should changes be made. You have what you have and you are what you are in business. There's absolutely no guarantee that fifth edition in pandering to the complainers will sell more product.
However, there's an absolute guarantee that they will:
a. dilute their existing product
b. still need to deal with Pathfinder, which is awesome.
c. have to expect that the complainers will buy a product that's similar to one they already have.
d. presume that the complainers are even playing the game in the first place.
Some of this is safer to presume than others.
One thing I would feel safer assuming than all of this is that real, successful executives that know what they're doing, aren't working for a family game company.

Respect meant where appropriate to Hasbro and WoTC.