It is not necessarily "silly" to consider the possibility that gravity may behave differently in mega-astrophysics, but rather it is an open question that scientists continue to explore. In fact, the behavior of gravity in extreme astrophysical scenarios, such as black holes and the early universe, is an active area of research.
The reason we have separate theories like general relativity and quantum mechanics is that they have been successful in describing gravity in their respective domains of applicability. General relativity provides a robust framework for understanding gravity on macroscopic scales, while quantum mechanics describes the behavior of matter and energy on microscopic scales.
However, when gravity becomes extremely strong, such as in the vicinity of a black hole's singularity or during the early moments of the universe's existence, both general relativity and quantum mechanics encounter limitations and are believed to break down. These extreme regimes are precisely where a theory of quantum gravity is sought to provide a more comprehensive and unified description.
The challenge lies in reconciling the principles of quantum mechanics with the principles of general relativity to formulate a consistent theory of quantum gravity. This is an ongoing endeavor in theoretical physics, and various approaches and conjectures, such as string theory, loop quantum gravity, and others, are being explored.
The point is that we currently lack a complete theory of quantum gravity, and until such a theory is developed, we can only speculate about how gravity might behave in mega-astrophysics. It is plausible that our current understanding of gravity may need to be modified or extended to properly account for these extreme conditions. Scientists continue to work on theoretical frameworks and experimental tests to shed light on the behavior of gravity in such contexts.
In summary, while it is not "silly" to consider different behaviors of gravity in mega-astrophysics, it is an open question that requires further research and the development of a comprehensive theory of quantum gravity to provide more definitive answers.