I don't think there is much relevance here. NATO is not a weak military force, if we consider the members defence hardware involved.
NATO has a potential of around 3.5 million troops covering Army Navy and Air Forces. Russia around 800000 (trained professionals).
NATO has around 4000 Combat Jet Aircraft. Russia has around 1200, some are old frames to say the least.
NATO has around 9000 MBT's. Russia around 3000 and some old relics in a barn in Siberia somewhere...
Off the top of my head, NATO has around 15 aircraft carriers. Russia has 1 old knackered one...
You get the picture, NATO is not short of military hardware.
It isn't however it doesn't really put fear in the enemy's eyes either, the us is by far the biggest contributor both in troops as in material.
The issue is it's all on paper for NATO and in an 'ideal scenario' type of deal. Troop and hardware commitments by member states can be flaky at best, Member states may differ on responses to crisis and the command structure is such that a NATO commander has limited authority over the forces. For example, the NATO commander could not punish his troops for failing to obey a lawful order, dereliction of duty and even if the soldier pisses on his shoes, the commander is powerless... Russia doesn't have that problem. Russia's unity in organisation, structure and command is far superior. It should not be underestimated...
Believe me as a Dutchman i know, i happen to know a few friends who served in Sebrenicia as an unarmed peace force with the promise of air support of needed, the air support never came, it was all under uncr/nato umbrella. But the us decided against air support on the last minute so it didn't happen.
Trump has said a lot of cack. But he was referring to the NATO requirement to spend 2% of their GDP on defence. Most are not... Frankly, whether it really would make a difference to Russian foreign policy makers as to whether Slovakia was spending 2% of their GDP on defence or not is up for a mickey mouse style debate. We all know the answer...
Sure he did, but if the Us is the biggest contributor he has/had a point in my view and i know the 2% isn't met, if they only started meeting it when Trump said so it wouldn't have made a difference but if they started 20/25 years ago i might have been a different story. Alltough not all of it just like you said the command structure is also an issue.
Russia knows it can push the boundaries. It knows that many NATO members severity of response is likely to differ as in part they rely on them for fossil fuels. It knows, NATO will not intervene militarily in Ukraine, a non-NATO country. There is too much at stake for NATO and Russia can simply absorb the sanctions and if we're being honest, the gas will continue to pump and in 12 months Russia will like be moving ahead with Nord Stream 2 again. The only way to hurt Russia, is the only thing keeping tens of millions warm and with power to their homes...
Sure but NATO should known his weaknesses, and thus not expand, whether it's as a candidate/aspiring membership or an full membership if they can't keep the promises as the military alliance provide. It does'nt take an rocket scientist to see NATO vs Russia was'nt going to work, so why offer an membership if you can't deliver on the expected protection?