my pediatrician wouldn't clip my son's tongue either. my husband was born tongue-tied and was never clipped. his older brother was clipped--born in a different state with a different pediatrician. my husband wanted my son's tongue to be clipped, but when I pressed our pediatrician he thought it was unnecessary.
my little boy will be three in three months. he speaks very well, and the only thing that might have been a problem is breastfeeding, but that wasn't our only problem, so it may not have worked anyway had I found someone to clip his tongue. my husband's reasons for wanting our son's clipped were so he could stick his tongue out and kissing! haha. I thought that was funny. but, I think my husband's way of sticking his tongue out is very adorable, and his kissing is great too. haha. hope that's not too much information.
I think pediatricians these days are not so into changing this for some reason. I'm just letting you know you're certainly not the only one, and an uncooperative pediatrician isn't all that uncommon either. I wish you the best!