I didn't see any mention of angular momentum. If a gas cloud has essentially no angular momentum relative to its center of mass, it will collapse directly into a BH, no?
There are a bazillion ways to rotate but only one way to not rotate. I'd say that the probability of a gas cloud without angular momentum is as low as to be indistinguishable from zero.
It's all spinning around the BH, and spins faster the closer to the BH it is. It was actually the core point of this particular experiment to measure how fast it's spinning; the paper's title is "A direct black hole mass measurement...", and the way they're doing that is "dynamical BH mass measurement"—i.e. measuring how fast gas spins around it, and applying kinematic laws.
If angular momentum exists, you get a galaxy.