Let me approach the question differently.
If Fourth Edition is indeed superseded by a version which appeases the fans of other editions, I pray to God that Wizards opens up the GSL, so that players who enjoy Fourth Edition now can continue to play it.
Players of other editions are very lucky. Because of the OGL, we can play any edition from OD&D to 3.75 without any limitations. I dread the replacement of 4E, because the current restrictions surrounding it will mean it will wither on the vine.
WotC created the GSL to kill off 3rd party support and thus competition. It was all about getting a larger slice of the pie even if the pie was smaller. By doing this they helped launch Pathfinder and further fragment the market.
One phrase I like to quote for this type of behavior is "being hoisted by his own petard".