Available? Perhaps. I could probably order one online and it might be supported by ATT (the carrier I chose due to great LTE coverage in my area). I'd probably be without warranty coverage and definitely wouldn't have a local place to handle issues or exchanges. Still, I could do so. Of course, then I would end up paying the full cost of the phone while also paying rates that "include" a phone subsidy. Yes, the subsidized phone model might suck, but it's what you go with if you want solid LTE coverage in my area.
So, assuming I don't want to do that, let's look at what ATT has on sale as far as Android devices...
Galaxy S 3 (too big), Galaxy S 4 (too big), Galaxy Note (huge), Galaxy Mega (it's a tablet - not a phone), Galaxy Rugby pro (thick, bulky, and intended for a different audience)
One mini (not bad, but not out when I bought my phone), One VX (too big), Optimus G pro (too big), One (too big)
G2 (huge), Optimus G (too big)
Terrain (odd form factor)
So, as far as high end Android devices being available in all sizes - perhaps, but not readily availble to me. Why would I deal with all those issues when the iPhone (a great all-around device) is sitting right there?