Earlier quoted context omitted.
A lot of it is because transportation is quite difficult. Even today huge tracts in Russia are without any roads. On the opposite end of the spectrum is the US, where even before the railroad and the automobile, transportation was quite easy, with navigable rivers flowing through the best farmland in the world. Another big piece is how easy it is to invade; how hard it is to defend. History records 50 invasions of Ru…
On the other hand, this doesn't explain why Poland, which was even wiped off the maps for a few times, has a GDP per capita almost twice of Russia, which wasn't really invaded much throughout more-or-less-recent history (au contrary).
I think a country like Russia is still influenced by its experience centuries ago (when it was invaded for a time every single year) and by its experience in WWII. One can argue that (because of nukes and because satellite recon and cheap drones give a tech advantage to the defender) Russia is in a new situation where it can relax and start worrying much less about invasions, but I think that even if the leaders of a country realized that, it would be hard for them to actually change the country. I think for example a big reason that the US is so rich is that (for the white settlers) life in America was always easy. The economy has changed drastically since Colonial American times, when most adults were farmers, but the experience of plentiful high-quality farmland (especially when the settlers started crossing into the Ohio Valley) and plentiful timber and rivers that were a great help to transportation even without doing much work to improve the river system (by adding canals for example) produced a culture that remained adaptive and useful even as the economy was transformed by steam, railroads, the telegraph, cars, electricity, etc.
Germany for example introduced a welfare system in 1871 IIRC. For the average commoner to make a living in Germany was hard enough that the German government of that time (who cannot be accused of having been bleeding hearts) considered it essential to national security for the government to help the commoner out. In contrast, when (many decades after Germany introduced welfare) the Dust Bowl devastated large regions of the US in the 1930s, there were no governmental programs to assist them because most Americans and most American decisionmakers considered such programs to be largely unnecessary.
I believe these governing traditions in the US (which started to change in the 1930s with the election of FDR, who transformed the country more than any previous president except maybe Lincoln) of small-government and individual freedom were conducive to wealth generation whereas the Russian governing tradition where a powerful state is seen as essential to protecting the nation from invasions and where the population tends to depend heavily on the government for its economic security tends to keep a country poor. And again I hypothesize that these governing traditions are difficult to change.
And maybe the reason Poland never develop a strong national-security culture like Russia did is that it was in a hopeless situation with respect to invasions and such (except during the ascendancy of the Polish-Lithuanian commonwealth, but I don't think that coalition lasted long) because it was surrounded by more populous, more-cohesive neighbors and did not have much in the way of mountains or bodies of water to slow down invasions from those neighbors: namely, France, Germany, the Austrian empire and Russia. In fact, I believe even Sweden invaded Poland at one point (although it had to cross the Baltic Sea to do so). No matter how much the government of Poland invested in national security, it wouldn't have been enough to move the needle much. In contrast, Russia was a big enough country with enough natural resources (e.g., good farm land, timber) that if it tried really hard over a span of decades, it usually could increase its national security considerably, which led to a national culture that emphasizes a powerful state with a powerful army (and a powerful spy system to suppress uprisings by already-conquered ethnic minorities).
Also, it is in the national interest of the US to prevent Russian re-expansion westward, and between 1989 and 2022 its main two allies in this regard were Poland and Romania (with NATO taking a secondary role), so after 1989 Poland could feel secure (at least till Trump came to power) without having to spend much on defense whereas Russia has felt (and still feels) that they are 100% responsible for their own national security.