They have a square inch (give or take). And you think that increasing the size 46 times is too little? In electronics things move fast, and more often are multiplicative rather than additive, but to increase something 46 times over takes several years, at least.
We now have 4Gb sticks of DDR3 RAM, I'm not aware of anyone who makes an 8Gb stick. 1/46th of 4Gb is ~64Mb. How many years ago was it that the biggest RAM stick you could buy (with infinite $) was 64Mb. I know it was more than 10 years ago, my Dell purchased in 1998 had a 64Mb stick.
Sure, we'll reach the 2Tb capacity, will it be in "a few years", 3-4 years isn't THAT long. Maybe, but I doubt it. Either way, they'll just change the standard. There may be some significant electronic or exFAT reason for the 2Tb. It's not likely they just picked an arbitrary amount.