Is there even enough time for that?
There's way more time than people think. Two more books the size of ASOS and ADWD, he thinks he can get it done in that, that seems to be the minimum.
ASOS is not just huge, it's dense, heaps happened, it moved fast. It was on the back of the set up in AGOT and ACOK, like they were the uphill climb and ASOS the downhill descent.
AFFC and ADWD are set up books like AGOT and ACOK, the slow uphill climb, the downhill is about to start. There's two books of downhill though, because it's not just AFFC and ADWD that's getting resolved, it's those and everything built on in the first three too.
No more new POVs. And POVs are inevitably and by his own admission going to start dying off. Those left are going to converge, as they've started to. Theon and Asha. Brienne and Jaime. Barry, Vic and Tyrion. Arianne and JC. All the characters in the east are coming back west.
The internal middle slog of the character arcs has been done. The world building is about all done, it's as wide as it's going to get, the scope of the story is set to shrink from here. And with still so much content left, massive amount of plot is going to be covered.
One way to think of it is ASOS was basically split between two seasons and still they cut out heaps. If they did the next two books in two seasons each then we are now just one season past the middle of the show. Instead they're talking 7 with 8 a possibility, and to get there they're cutting out Aegon and whatever else.
In the original abandoned plan the dance with dragons was the middle of three stories, we are still a bit away from the beginning of the dance. In straight volume, if he finishes in the amount of words he hopes, we are around two-thirds through the series.