If you look at the PC market, the overall speed of CPUs is going up MUCH faster than the average clock speed. So even if it was the same frequency as as the last one, you could still count on a sizeable boost, the fact that it's 50% more is very good news.

We are talking about frequency specifically.. so the Pro is 2.1 Ghz. A 50% boost is about 1GHz. So the PS5 would have a frequency of about 3.2 GHz. This is tremendous considering the Zen 2 is already light-years ahead of the Jaguar. A 2 1GHz Zen 2 would destroy a 2.1 Jaguar and even a 3.2 Jaguar.

cpu will be 3-6x times better than current gen.

Frequency determines how fast a chip can process a command instruction, or how fast each cycle executes within the chip itself. It isn't a full measure of how many instructions can be processed per chip cycle.

For example, the CELL in the PS4 was about 80% faster than the PS4 APU. While it could process individual commands 80% faster(disregarding other system bottlenecks), the PS4's APU can process significantly more data in the same cpu cycle due to the amount of processing functions it has within it's architecture.

Between two equal processors....say if you took two i5 processors of the same type, the higher frequency means it could process the same amount of data faster, but not necessarily more per cycle. You'll get more overall data processed within a set time frame with higher clock speeds in this scanario though.