Depending on how much mass has accreted around a black hole's event horizon (without actually falling in), a black hole might actually behave like a hollow sphere, with no net gravity throughout most of it's interior. A flat, undistorted spacetime might exist inside. If virtual particles are being created on the event horizon, and anti-particles are selectively allowed to escape, perhaps because they spin in the opposite direction as the black hole, this might explain why the interior is dominated by normal particles. And if the visible universe is a black hole, then that might explain why the visible universe appears to be getting larger, because everything inside is stretching into a deepening gravity well, but without a singularity at the center. If the destiny of the universe is to eventually accrete all matter into supermassive black holes, then maybe it has already happened. That might be the natural state of things.

Of course I don't have the background in physics to hypothesize this with any confidence.