Incorrect. Any growth in a system of finite resources is sigmoidal, with an exponential portion early in the curve before diminishing returns kicks in.

We've been promised this since the 90's, and, yet, we've been pushing back the wall Moore's law was supposed to hit for more than 30 years. And we haven't even properly started to play with non-transistor logic and analog neural devices, so I am cautiously imagining we'll remain exponential for the time being.

It all depends on where we are in the curve.

We are at the stage we are starting to explore the possibilities of using analog components, so my guess would be there is a lot of road to cover.

Plus, there are a couple different lines of research for new materials as well, so any one of those can yield something interesting.