[snarks_when_bored]

Physicists who work at the fundamental level fully understand that General Relativity breaks down at the Planck scale and also that Quantum Field Theory isn't feeling so good at that scale, either. That's why they're searching for an over-arching theory that transcends (and subsumes) both GR and QFT. Superstring Theory, it was hoped, was such a theory. That hasn't proved to be the case...yet.

[Southack]

"Physicists who work at the fundamental level fully understand that General Relativity breaks down at the Planck scale..."

It's more than that. GR contradicts QM in regards to universal Gravity and energy.

...And even Einstein himself had to delete his Universal Constant from GR after 4 decades of scientific denial...

[Ernest_at_the_Beach]

An interesting reference here:

Noncommutative Geometry for Pedestrians