Is the Kremlin a Scarcity Based Argument?

My personal view is that this is actually a conscious decision by the Kremlin not to escalate because of concerns over a response from the West. Obviously they're concerned just as we are about escalation in this war and they do not want us supplying long-range missiles like attack them to Ukraine. They don't want us to get it directly involved in this fight. Anything that would potentially trigger response from us may actually be more detrimental to them than helpful.