[AlotOfReading]

Terms like 'turkic' really only serve to confuse discussions like these. If you're asking whether population continuity with modern day populations in the area is a reasonable and common null hypothesis, the answer is yes. There are cases where continuity is extremely limited (e.g. pre-Columbian native Americans -> modern rural American populations), but those sorts of near-complete replacement events are historically rare. More commonly it's a broad mixture of the admixture, social recombination, and ethnogenesis that's constantly happening anyway.

This is all separate from saying that historical people would have identified as 'Turkic' or 'Russian' etc, or even understood anything resembling modern definitions for those terms.

One of the hallmarks of colonial archaeology was conflating these things and throwing in a touch of racism for good measure. They'd walk up to a Mayan site (ex.) and say "well these modern primitives couldn't have invented the techniques for this fine stone- and metalworking on their own, therefore a group of now-extinct people who suspiciously resemble Europeans must have either done it directly and been replaced or taught these barbarians how to do it". Thor Heyerdahl of kon-tiki fame is a prominent example that you may have heard of, but this was a thing that permeates a lot of old archaeology/anthropology. There are even terms for this like diffusionism and hyperdiffusionism. Being called a diffusionist is basically one step above being accused of plagiarism for modern archaeologists, which should give you an idea of how badly such theories are regarded today.