Monthly Fees

You lie awake at night worrying about what is that which will disrupt your business model - Randall Stephenson

I have to admin that I'm impressed in all sorts of ways with ATT.  I bought my very first phone from ATT Wireless which became Cingular which became ATT.  I held that original "ATT Wireless" SIM all the way through my iPhone 3G.  It mildly confused Apple geniuses at one point when I went in for repair and they told me they thought I had a knock-off SIM card.  No - sorry, it's just really old school.
As an old-school iPhone owner I am blessed grandfathered into the $30/unlimited plan.  I run about 2GB/month, so my only other option would be the $30/3GB plan which obviously makes no sense.  Even Mrs.Chaos is grandmothered in to her $25/2GB plan.  At her previous job she had no WiFi, and needed all that data.  Now that she is WiFi at home and WiFi at school she's running pretty low data rates.
ATT just rolled out the new "family data plans" which I quickly went to review.  Family data you say?  That sounds like a fabulous.  Since we jointly use about 3GB's of data, perhaps we can save as much as 50% on this?  So what is the cost of family data for our family?  We have to get the 4GB plan which is $70 + $40 for each smartphone.  Total cost to us?  $150/month.  I'm having a really difficult time understanding how this could be a less expensive option for anyone.  Can someone help me out here?
If you had five smartphones on 5GBs.  Old plan $250/month - new plan doing a shared 6GB is $265/month.  So if you have five devices and want to cut your bandwidth from 25GB/month to 6GB/month you can pay an extra $15?  I feel like I'm missing something... and yet... I've run all the calculators on the ATT site and it agrees with me.