To recap: this is what we’re discussing. At least, if you mean “ask new users if they are new, and assign them a suitable glicko rating”. Or do you have a different solution in mind, for what we do with self-identified new people?
The problem is purported rank pool drift.
As Vsotvep says, until someone “does the numbers” (actual maths with actual realistic numbers) I don’t think this proposal has a chance. Proving that rank-pool-drift will not be a problem requires an actual proof, not supposition or theoretical arguments. Similarly, assuming it will be a problem (because anoek did numbers and asserts that it will) any solution will need rigour in explaining how it avoids that problem.