Cassandra,
I know exactly what you mean by airy, spongy. Many of my trees have the same problem. Your lone almost ripe fig looks better than mine, LOL. A lot of my trees that were good producers of delicious figs last year have failed to produce an edible fig. They are shriviled, spongy, and finally drop off. Inside is immature, dried up. Dehydrated, as Jon says.
It has been very hot here and dry. Lots of thunderstorms but very little rain that hasn't done much good. It dries up fast in the heat. I've had to water daily and judging by my just received water bill I wasn't negligent in watering them.
The one larger fig that is hanging on is still soft and spongy. I'm waiting till it is ripe, if it hangs on that long, then I'll cut it and see if there is anything inside. I'll let you know.
Peg
CT, zone 6