Why we do not see cheap DDS for high frequencies on the market?

Modern microcontrollers and some ARMs run at GHZ clock frequency, why they do not put some delay meanders and start making nice DDS chips? It does not need to have any huge memory, only few constants for waveform generation. Even with low output power it would be a good thing, assuming HF transistors are not so expensive to add few dB to output...

the processes available are most likely limiting the ability to do the mixed mode DDS type circuit functions at a higher frequency. You can buy a GaAs one if u need, but it will costs thousands of S probably.

AD seems to make some nice DDS chips, what do you want to do that they can't do? Those microcontrollers and ARM chips are in small feature low voltage CMOS, so I'd suspect output levels would be pretty low.

So why not making DDS with low output power and put two-stage cheap gaas FET amplification outside?
Or even hybrid: cheap cmos DDS + 2 gaas fet crystals inside one IC.

Sure, they could do this. Why would they? What's the market, and how big is it? Compared to their integrated PLL/VCO parts, what would the advantage be?

understood