Re: They only need smaller cells for higher frequencies
The big selling point for 5G is not bandwidth, it is latency. Low latency is how 5G is supposed to allow control of devices (e.g. cars, robots) in real time. To obtain high latency short symbols are needed.
The problem with short symbols is that they are susceptible to multipath distortion. And, for all the promise of technologies like MIMO and beam-steering, the best way to fix multipath distortion is to shorten the path length. That is, to have smaller cells.
Carrier frequency doesn't change that.