Why? Because PDF is a military based forum. It has been to long for us to get some worthy military analyst that can broaden our horizon. Well, at least for me, a fan boy who want to learn.
Its obvious that militarily, Ukraine is getting crushed. But its also true that NATO has tremendous capability and almost unlimited resources to fund an insurrection and hurt Russia very hard many many tomes greater than it did in Afghanistan. Ukrainian army is very sophisticated. Its soldiers speak Russian and look Russian. Armed with NATO intelligence and weapons they will absolutely destroy the Russian army in the long term.
At the same time, Ukranians can much easier identify the Russians pretending to be Ukrainian, because Russians dont speak Ukrainian, especially if they are form central Russia or Moscow and especially if they are from caucasus.
I would be very worried if I was an occupying force in Ukraine.