Due to "race mixing"(misegenation), every person on the planet will have the same color skin

No it does not make it true because we don't know for sure what will be the result of people's physical characteristics . Like it was mentioned, there have been cases where the children had physical traits that were unexpectedly unidentifiable to that of the parents . That was because of what ? Because of the genes and the ones in particular alotted to the offspring . When the research is done you will find that this is possible to happen. Genes do not work in the fashion in which we can accurately predict what the appearance of a being will be . We can have vague , obscure ideas in reference to the composition of the being. But to calculate with 40% here and 60 over there or just plain 50/50 and it all averages out, it's not so cut and dry. Genes in the DNA mutate , broken sequences are replaced known as the dominant over the recessive . A gene that comes from a great grandparent that goes into the child which gives the child a trait that's not quite resembling to the parents was more than unanticipated. We have no definite determination of those details . Also mentioned previously and again how long has intermingling of the so called races been going on and what does it look like today? Racial classifications are based on societal declarations. How can a dark skin person and a light skin person both be called black when they're two different colors and this whole system is based off of color of skin according to you defining as that ? Societal regulations lumps them altogether. Doesn't matter the difference in genetics no matter how significantly different or variation of skin tone . Hence where that one drop rule comes into play . Even some "bi-racial " folks say that they are black . They are not white and black , they are not white , they are black . It's how they see it and society agrees . One person I knew and another who said " I am black, Mexican/Hispanic but I consider myself African-American ". It's already been established that the racial system is dictated and relative . The point of discussion is about physical characteristics and the outcome of people reproducing in a intermixing fashion as one might say. Furthermore with the groups that don't step outside there group . The ones that "stay in their lane". What's makes the topic statement also inconclusive is that people that "stick to their own " , what makes you think they will stop sticking? As far as I'm concern the likelihood is that there always be not just in rural areas but in the cities too, that there will be generation after generation of people reproducing with people of the same people group . Unless a predictor is making the same claim as being true like the topic statement . That they know that the trends are going to change . People are going to get bored , people are going to get immensely curious and the momentus part of all , prejudice will be a thing of the past . There won't be nothing that stands in the way , no barriers , no alienations, demarcations and or separations of nothing and nobody to produce this one race world . Which once more , I believed already existed . So since this is believed to happen , how many years would all of this take? A ballpark figure is fine.