Think about it, he is seemingly immortally young. As time went by from killing C-137 Rick's family until present timeline of the show, he(Rick Prime) probably noticed it is a tedious work to recruit Ricks from other dimension, so he probably cloned both himself and his own consciousness across other dimensions,

Why else we would see the exact version (in age) of our Rick each time when our main Rick and Morty skip dimensions. What caused that each individual Rick to appear at Smith's home in each dimension in the first place? Did they done the same as our main Rick skipped their own original dimensions.

All we know so far is that Rick Prime probably wanted to create his own citadel of Ricks (with constellation of three stars) prior to RickC-137's hunt. After seeing that recruitment of his versions has it's own flaws (by giving his own technology to other versions of himself mother to let them), Rick Prime probably realized it's more simple to just clone himself both physically and mentally many times over across other dimensions, rather to recruit versions of himself who are nowhere near in intellectual potential as Rick Prime.

And when in 1510 episode when "Evil" Rick(that was actually controled by Evil Morty aka Eyepatch Morty) categorized the Ricks from most evil to least evil, he listed himself the most evil, while he listed our Rick(C-137) 3rd most evil, right between "Evil" Rick and C-137 there was a "SuperWeird/Murderer/Killer Rick that is now known as Rick Prime. The "Evil" Rick remark at Prime Rick listing hin the second most evil Rick with following sentence: This guy here... Super Weird", probably guessed that even the most "evil" Rick won't even bother to have anything with Rick Prime, it's not like he is scared of him, but it would be just waste of time just to play "games" with this guy to get trolled by him in the end.

My take is that each Rick that have lived in currently ex Citadel of Ricks (that C-137 helped to build) have their own rouge Rick (like Rick Prime), Those rouge Ricks were probably all killed during C137's hunt for Rick Prime, but Rick Prime by the time the current Citadel of Rick is created, he created so many clones of himself across all different dimensions (probably all the dimensions where the versions of Ricks are dead).

Thats why our Rick(C-137) answers to Morty's question after salvaging the information from Rick Prime's killbot "I wish Morty, it's all the places he is