I have a hunch
Russian progress in the invasion of Ukraine is not going to plan. That is evident from negotiations between the warring parties as I write this piece. I have seen photos of burned out military vehicles and speculate that they are Russian. Back during the end days of WWII when Soviet armour invaded Germany from the east, Germans were issued with large numbers of shoulder mounted anti tank weapons to help slow down the onslaught: Strategically positioned, one man could take out a Soviet tank in short order. And that happened. Fast forward to Ukraine, shoulder mounted missile launchers are an order of magnitude more effective than in WWII with smart missiles actively seeking their targets over the course of their trajectory. Sitting inside a tank these days, is sort of like being a knight in shiny armour, in the face of a lead ball from a musket. The tank becomes your coffin.