Will the universe become a black hole?

I love space, but I'm a don't know much about it, so I apologize in advance for my lack of knowledge.

From what I understand, theoretically, galaxies are built around supermassive black holes that slowly "absorb" everything around them, hence the spiral shape. By "absorbing" other celestial bodies, they gain mass and grow larger and larger.

Question: Is it theoretically possible that in the very distant future, all the black holes in each galaxy will eventually merge with each other, leaving only one immense black hole in place of the universe?