It's implausible to you and I from our vantage point, but not to Russians, who still celebrate VG day as one of their biggest holidays. Having a buffer between Europe and Russia has been doctrinal in Russia since at least Peter the great. Ukraine was supposed to be neutral after the USSR split. It wasn't until The EU and US started treating it like they were going to extend it membership in the EU and/or NATO that Russia stepped in. The amazing thing is that our diplomats didn't foresee the result. Or maybe they did, and their great game style thinking wanted to provoke Putin as a way to try to get his citizens to turn on him. That clearly hasn't worked. Yet.
It probably won't anytime soon :( Russians are good at bottling things in and being serviant for the longest of times. Serfdom in Russia was pretty terrible: it was pretty much slavery without the race component and it dragged on for ages. Then there were the horrors of the soviet union and Russians just took it. It sometimes feels to me like being fucked by the government is the main component of Russia's National Identity and it creates a sense of community in a way... I read Russian forums from time to time and stuff like "Things are crappy but we're Russians and we can take it until it gets better" is very common rhetoric. The majority thinks it's the West sabotaging Russia and protesting the government is giving in to the West. :(Yet.