I know the numbers are given by Blizz, but I did one A1 run in 30 minutes.
I found 3 ilvl 63s and sold them for 9 million on the AH (after tax).
I did multiple Siege runs today (~6-7?) and pretty much got total of 2.5 million worth of items.
The runs only take me 20-25 minutes on my barb, but it is quite boring to do multiple times.
I feel like the breeze through elites in A1 and the number of elites you can bump into makes you truly benefit more in the long run, UNLESS you can walk through A3 already, then more power to you.
I can rambo anything in A1 and A2 solo, and A3 tends to still need a bit of kiting/dodging for my barb, although I do plan to upgrade plenty of my items soon with ~30 million gold.