Extreme summary, blame me if I missed something obviously important - unsupported tanks will die to infantry or artillery and have done so since shortly after the inception of the tank. Tanks are actually pretty cheap compared to replacing a human, it costs quite a lot to raise a modern human. The tank role still exists, but ratios of tanks to other fighting vehicles may change.
https://www.youtube.com/watch?v=mUyAPQEb01Q
Chieftain
https://www.youtube.com/watch?v=lI7T650RTT8
Bernard
https://www.youtube.com/watch?v=QPth_xqBXGY
Extreme summary, blame me if I missed something obviously important - unsupported tanks will die to infantry or artillery and have done so since shortly after the inception of the tank. Tanks are actually pretty cheap compared to replacing a human, it costs quite a lot to raise a modern human. The tank role still exists, but ratios of tanks to other fighting vehicles may change.