I think it's true that doping can put athletes into the same tier and others over the top but east Africans have been dominating the 800 on up going back a pretty long time. it helps to have a culture where running is the top sport and to be at altitude with good genes.
Running is the top sport and doping is prevalent. They have the body type to produce sub-elite runners en masse without doping, and with doping, a degree of domination. Would they be dominant or even winning without doping? We don't know yet, and might never, but we can observe that as testing increases, the busts increase, and times go backwards.
There is no evidence that altitude will lead to 'domination' at 800m. Peruvians and other peoples live their lives at altitude and dominate nothing.
With the rampant doping going on in Kenya that is now evident with every new bust, it they had a superior genetic advantage, and given you yourself state it's the most popular sport, their domination would be way more than it is. Only two Kenyans have ran faster than Seb Coe did four decades ago on much inferior tracks, in worse shoes, and with far, far worse pacing and competion. Only two Kenyans have ran faster than 3:27.6, a time that surely Elliott, Ryun, Cram, Coe, Ovett would be running today, and both those Kenyans failed tests (or at least with Lagat, failed half a test).
It's quite possible that they wont win a gold in any male track event this year other than the steeplechase. It's quite probable they wont win a gold medal in any male track event next year in Tokyo other than the steeplechase. And that's before any of the busts of their favorites that are likely to happen before or during the Tokyo Games. I think Kenya sent seven male runners to contest the 800, 1500, and 5000 at the 2017 WCs in London, and 3 of them have already been busted (Kiprop, Bett, and Rutto). Two of them were medalists.
To continue to ignore the overwhelming evidence of doping in Kenya and the contribution it makes to their success is quite sick at this stage, especially given the demotivating effect it has on young athletes from other continents.