There has to be some other important factor here besides the JCP grants though. A whole bunch of MN teams were founded off of those grants back in 2010/2011 as well, but almost none of them have folded.
Here are the relevant documents I could dig up:
2010 (I think) JCP sponsored teams
2011 JCP sponsored teams
According to the second document, JCP sponsored 21 Rookie/2nd Year Teams in MN, and 28 in TX.
As of the 2014 competition season:
only 2/21 of these MN teams are inactive (3747 and 3524)
14/28 of these TX teams are inactive (3819, 3758, 3409, 3713, 3778, 3730, 3392, 3804, 3857, 3696, 3369, 3529, 3762, and 3869)
Perhaps it is not a useful analysis to compare MN to TX, since both regions seem to be outliers in terms of growth/sustainability (on opposite sides of the spectrum). I'm just curious as to why MN seems to be doing so well in this area, especially since there were no sustaining teams here prior to 2006.
Maybe since MN didn't have very many other robotics programs in 2010-2011, the teams here didn't really have the option to "drop down" to a less resource-intensive competition and thus were forced to stick through the sponsorship crunch? That seems silly, but I can't come up with a better explanation.