The reason his assertion is false as the growth of Android is not tied to a single carrier or device. It has more to do with the OEMs adopting Android over Symbian or WP7. Motorola became cashflow positive by using Android. HTC can't keep up with demand.
Growth is not tied simply to the US market either. Android usage is exploding worldwide specifically with cheap handsets in huge countries such as those in SE Asia.
So Gruber, blinded by his own fanaticism, actually thinks Verizon's iPhone offering is going to compete with 50+ OEMs' adoption and usage of Android? I think not.