Have noticed this also, Nikki, though not with great frequency.  I think a first time mother is so-o-o nervous, maybe that alone impairs her supply;  or maybe she didn't have adequate help the first time around to help correct the problems, coupled with anxiety, and lack of sleep.  So she regrets that she can't supply baby's full needs, ends up at least comfort nursing (we hope), and goes on to do the best she can.  Next baby:  voila!! she is now more relaxed, her first baby has survived the traumas of the first nine months, year, whatever, and mom has more confidence in herself as a mother, as well.  She'll try breastfeeding again, but if it doesn't work, well, it's not optimal, but it is okay.  All the pressure is off, and lo the milk pours.

Warmly,  Chanita