Why don’t we instead terminate NATO? Or, give NATO members a chance to provide equal funding or resources, else be kicked out of NATO? Why are we still wasting money with this and defending Europe?!
Because Russia will not stop invading and threatening its neighbors.
Perhaps because we tried it your way (no NATO) twice and it turned out badly both times. Add to that further experiences with Russia's desire for global conquest which apparently did not die with the Soviet Union.
Because we think we are still a superpower.
You heard the famous dictum “those who ignore history are doomed to repeat it”?
History tells us ancient empires met their demise by over-extending their military in foreign lands.
Latest example is Hitler’s Germany sending military deep inside Russia.
Here is the sad truth, no one can be a superpower with debt bigger than GDP. Currently our national debt is 35% bigger than GDP.