A number of economists and commentators, including me, have raised the question of how the Russian economy can sustain such a powerful military force with such a comparatively weak economy, one with a Gross Domestic Product roughly equivalent to that of Spain, a relatively prosperous nation, but certainly no military heavyweight.
The simple answer is that Putin and the oligarchs direct more resources proportionately to the military than other industrialized nations, and much of that funding comes from agricultural and natural resource exports. Some comes from the depressed wage structure that requires labor and services, even high-skill services, at little more than survival level, if that [which, ironically, is an improvement over the 1990s, and one reason why the Russian people put up with Putin]. And some likely comes from plundering re-conquered parts of the former Soviet Union.
The Russians also steal any technology that they can, so they don’t have to develop it, and rely on foreign suppliers to provide parts for some of their industries, because they’ve never been able to afford to develop those technologies. At times, they’ve been unable to produce advanced weapons systems they’ve developed because they lack the funding. They’ve announced ambitious ship-building projects, but in reality, the actual numbers of new vessels aren’t that large, and most are submarines or smaller surface or amphibious ships. At the same time, they have difficulty maintaining and operating all of their existing fleet, particularly capital ships. They also lack the ability to gain clear air superiority over Ukraine and appear to be losing aircraft faster than they can replace them.
All that being said, Russia has a substantial backlog of artillery, ammunition, and tanks [if of older models] and the ability to induce/force men into the army as well as to stifle public dissent almost totally. So Putin will expend those assets until he no longer can, which could be years, based on the assumption that the U.S. and western European nations will give up before he runs out of artillery, ammunition, tanks, and the soldiers who are little more than cannon fodder to him.
And all that provides an example of why military-authoritarian nations continue to exist, because weaker nations can’t stop or contain them, and stronger nations that maximize individual freedoms often ignore them until they provide an imminent national threat.
In the natural world, parasites of all types tend to thrive right up until they grow so numerous or effective that they kill off the host organisms from whom they steal their sustenance. Seems like a parallel to what you are saying.