The thing is that whenever we find R1a and R1b in context of hunter gatherers, they are unmixed. We either find a group with only R1b or only R1a haplogroups.
It is normal thing, because HG groups are usually small, mostly families.
But as I showed you earlier, they are in the same region nearby each other.
This means that they had split and never mixed for a long long time, thousands of years ago.
Even if - they at the beginning could have one language and be one tribe.
Why it is so hard for you to accept?
The same is with Indians. Maybe they came 40, mabe 12, or maybe less thousands years ago, but when they did it,
they were probably speaking on one language, and were one tribe... so even if they cannot understand each other,
they are coming from one group of people, and their dialects are descendants from one pralanguage...
For that reason they couldn't have spoken the same language, even if they started with the same one 10 or 20 thousands years ago.
The same - maybe not, but dialects were of the same origin, which were later replaced by new dominant kurgan dialect.
And if we are talking of the last common stadium of IE, lingusts theorsied that common language could exist 4-40.000 years ago.
So it is not impossible according to your holy scientific guru's, that R1 tribe 10.000 or 20.000 y.a. wasn't speaking on PIE - as you was claiming earlier.
But as I said before - the same way one dialect could replaced others after some point of time, as for axampke Roman Lartin replaced other Italic languages.
These people are still Italics after all, as they were before...
In theory.
10 or 20 thousand years it is so huge period of time, and you even dont know which number is correct.
It is something like say: George Washington was living 10 or 20 thousands years ago.
So, when did he lived?
If language didn't evolve we all would still speak Adam and Eve language, or African language, depending what you believe.
So, if this is possible, that someone can belive in A&E, why did you banned a poll about similar question?
Instead we have hundreds of languages and thousands of dialects. And this points to rather fast evolution of languages.
So if you claimed that languages are fast evolving, then you make these tens or hundrets of thousands of years unemployed...