The future is unevenly distributed. My carrier offers 4GB for $35.68, up to 40GB for $71.60. Prices are flat across the lower cap-levels because they don't want to sell plans that small, they prefer selling larger chunks of bandwidth hence the cheaper averages. Their prices fall / caps increase fairly fast. We are currently receiving some special promo with a 100% increase in cap for free, it probably won't end as their prices will have dropped by the time they stop doing it.
Anyway, to get back to your original point - why is average transfer more important to you than peak rates? I don't watch youtube or netflix constantly on my phone, but when I do I want to to hit 80Mb/s for that period.