I have a different take. The restrained response of the West in supplying Ukraine with military aid reflects caution in trying to prevent a larger conflict potentially resulting in a nuclear exchange. As time has gone on, Putin‘s threats appear to be somewhat hollow, but I think much of the restraint you see is due to concern about a regional conflict becoming a Third World War. No one that I know in the West wants to see continuing misery for the Ukrainian people. We all wish the war would end sooner rather than later.
The United States, in particular, is engaged in a delicate balancing act. Putin is already trying to paint the war in Ukraine as an existential struggle between the West and the powers with which Russia has been historically aligned. By showing restraint in the amount and type of aid, the West is willing to provide Ukraine, so far this conflict has remained a local struggle. It could easily spin out of control if too much force is applied. You may disagree with the approach of Western Governments. Many do. Many consider the response too tepid and aid too limited. But the politicians are doing the best they can to balance larger geopolitical strategic interests against the tactical needs of a country that has been unjustly invaded by its neighbor.
The evidence that the West’s approach is for the most part successful is in the fact that India and China have, for the most part, stayed on the sidelines. They have condemned Russia’s inflammatory threats to use nuclear weapons. Since Russia is running short of supplies, its primary sources of additional war material are North Korea and Iran. This strongly indicates that the policy of containing Russia and the current conflict is in fact working. If massive force were brought to bear, China and India would quickly be required to take sides, and the delicate balance would likely quickly unravel.