Twitter was balanced on a knife's edge, but the owners were keeping it running and even earning a profit some years. Musk being a dangerous brand to put your advertising on is what pushed it off the edge of that knife.
But if you think "Pulling a profit every single year" is the only metric for success, I feel sorry for you as well. Twitter is insanely popular in most developed nations of the world. At least, it was.
The only thing killing it now is Musk, pure and simple.