I'm wondering if the days of a larger country easily "taking" a smaller one are nearing an end. Besides the obvious Afghanistan examples for Russia and the US:

1) In Iraq and Ukraine the initial weaponry phase was impressive, only to bog down on the "boots on the ground" phase. This has proven difficult because

a) If the subject country has any patriotic fervor, they are hard to displace by the "invaders", no matter what the invading country's cause.

b) With modern sensibilities, many the world over don't want to "die for their country" anymore (see D Trump for details)

2) The world is now indeed largely economically connected, so that the resultant sanctions prove costly in the long run. Many in Russia want to travel/business connect and don't want to be seen as pariahs.

3) Similarly, the world has evolved "rules" for war (ie Geneva Convention, War Crimes Tribunals) and presumably the perps don't want prison or execution for their crimes against humanity.

I keep thinking about Zelensky's show "Servant of the People" and how it has such a Western refrain (comically yearning for integrity and freedom), almost quaint and something we could learn from. I can totally see why Ukrainians are in "don't give an inch" mode...the alternatives are almost not worth living for (that, they say, is when "total war" kicks in.