True, IOTA will be bigger then BTC.

BTC simply can not be that huge how IOTA will become, because it is technologically not able to do what IOTA can.
To connect billions of devices worldwide.

While IOTA can easy do what BTC does, without any fees and much faster.
Bosch Venture Capital is the first company ever endorsing a cryptocurrency, giving the IOTA token a clear value.

The fundamental software of BTC is nearly 10 years old, of course there simply comes a time, where smaller updates cant help it to keep at pace with technologically superior projects. So while BTC and BCH fight about the blocksize, IOTA is inventing the warp drive.