If a person is just learning Russian to read scientific literature, their accent is not very relevant.  They might never speak at all.

To acquire a naive accent (which most adults don't manage no matter how many native speakers they talk to) I don't need to talk to a native speaker, I need to imitate a native speaker.  I can listen to native audio.  I personally do that long before I ever talk to people.  It is called "shadowing".  I can record myself and play it back and then try again.  That actually works better for me than speaking with somebody else at that stage.

I am not saying speaking with naive speakers is not important if you want to fully learn a language; it is important.  But your notion that it is "the best" way is wrong.

Pir

But it remains the best way to learn a language is talking with the owner of language
Do not forget that you will gain accent Owner of language

No.  There is no best way.  It largely depends on why one is learning the language.  If I want to read scientific literature in a foreign language, talking to random people isn't going to help me one bit.

It also depends on what type of learner one is -- I don't learn particularly well by just listening and speaking; I do much better when I first read and write a language.  Add to that what one's psychological makeup is -- a strongly introverted person won't be comfortable speaking with a lot of people.

So, while talking with native speakers will work well for some people, for others it will not be the best approach.  I know people who've lived in a foreign country for years without learning much of the language, and I know others who've never travelled there who speak the language fluently -- and that was before the internet and easy skyping.

I do not disagree with you
If you go to a country that speak a language you will learn language through only 4 months. If you need while I studied 2 years

No. I don't fully understand your post, but I disagree based on the principle that there is no best way to learn a language.