Why simple microwave ~3GHz prescalers become out of stock?

It seems that UPBs "/256" become out of stock? For example, at digikey. ADF PLLs with prescaler output is available, but needs external IC to write control registers. I want to make new frequency divider for my frequency counter with cheaper components. My old prescaler uses hittite IC, but they are expensive. Now thinking about ADF's. I found two PDF's with prescaler lists, but they are quite outdated. mc12054, upb1506, mb506, adf***. Which one to choose for newer design?