Big is in, clearly. Unfortunately, as I see it, it is because of two factors: 1) Technology allows for huge prints much more readily than 10 or 15 years ago; and 2) People are willing to pay more for a bigger print. Rich people have both big empty walls and big full wallets.
Regarding #1: Most of the huge prints are not good enough technically or aesthetically/artistically to hold up at the size they are being asked to support. Regardless of medium, there aren't a lot of Burtynsky's out there, fortunately for Burtynsky but not for the viewing public.
Regarding #2: I think economics (profit motive) has a regretable upsizing pressure on print sizes. I can only imagine there is a greater profit margin on a massive print than a 'small' one.
The digital age has made it too easy to scale up prints (I daresay most of these massive prints are digital, right?). But one thing hasn't changed in the digital photo age: A bad image is still bad, no matter the size... upsizing can even make a poor image worse.