Factually incorrect. If Nvidia dropped TSMC, TSMC could still sell to apple, AMD and others. If TSMC dropped Nvidia, Nvidia would literally have no other options for cutting edge nodes.
TSMC already sells to those companies, so I don't think that addressed the scenario. I would imagine that other chip fabs would be able to pick up the slack, including many that are purchasing from ASML already and are on track to begin matching TSMC from a node perspective in a year or 2.