Your characterization of him is correct, but he didn't accomplish what he did through sheer luck and marketing; he also had a really good sense of what (average) consumers wanted in a technology product, which his competitors seemed to mostly lack.
He failed to produce his own brand. The only thing that comes to mind when anyone thinks about Mark is "Facebook scandals", "looks, moves and talks like a reptiloid/robot" and "the mataverse that no one wanted failure (no legs!)". I bet he wishes he would have been what Elon Musk was, someone with pretty much his own cult. Elon Musk still has his cult followers and online knights despite his increasingly erratic behavior and general unpleasantness.