@Terry One doesn’t want a 2.1 tfr though, they want a 4-5 tfr. Russia has a lot of room to expand, and healthy competitors.
Europe’s population is 500+ million and is exceedingly wealthy and backed by the United States. China is 1.4 billion and arguably the largest economy in the world.
Russia has advantages, but why not fill out the interior a little bit? Especially with White Russians.