Something moving around does not show that it is a black hole that they are moving around. The lack of observed objects does not itself prove the presence of an object or that the object is what you think it is. The only proof shown is that something is affecting everything around it. A plasmoid could do that. Also, explain the galactic jets coming out of black holes or the need to come up with dark energy/dark matter to explain why they are missing mass that they cannot account for in their models. We have stars older than the galaxy and stars with transuranic elements, both should not exist. At what point do we decide to throw things out and actually rebuild theories.
Your thinking here is something I am aware of and agree with to an extant. There are stars documented older than the Hubble time for the Big Bang event. However, astronomers and cosmology department folks will hold to the paradigm until a better paradigm explains the observations. A good example of testing is all the debate and argument over geocentric astronomy vs. heliocentric solar system. Copernicus, Tycho Brahe, Galieo, Kepler, Newton, Cassini, etc. It took a long time to overthrow the geocentric model and show the Earth is moving, e.g. stellar parallax. However, the thread is about black holes so I will leave this alone. I do not know how to test and show supermassive black holes are creating the Big Bang today