I think the holographic principle and its, especially popular, interpretations are stretching things too far, way outside of the black hole as one can say. Ther

I think the holographic principle and its, especially popular, interpretations are stretching things too far, way outside of the black hole as one can say. There is so far nothing to indicate that the specific conditions inside black hole giving rise to the observed "holographicity" of the entropy of the black hole are applicable outside of the black hole. What we have - the space of possible states, i.e. entropy, inside a black hole has significantly reduced cardinality, i.e. it is equivalent to the cardinality of the black hole surface in this case. That means that either there is strong additional dependency/correlation arises between the states of the black hole components/particles (doesn't sound that unrealistic - we do have similar, using very wide notion of similarity of course :), process on the other side of the spectrum - Bose-Einstein condensate (and the similarity may be pretty high https://arxiv.org/pdf/0807.0315.pdf) https://arxiv.org/pdf/0807.0315.pdf)), and which in effect is kind of equivalent to the loss of some degrees of freedom, or may be there is a loss of degrees of freedom due to the black hole spacetime distortion - gravity distorts the spacetime, and the black hole is the ultimate case of it with the local time basically disappearing for the external observer, and thus we have a perceived loss of degrees of freedom - as observed by external observer. I.e. it may as well be that the entropy inside, as would be perceived locally, may still be "normal 3D" in the local spacetime while it is basically frozen from the POV of external observer (and thus what we observe is the projection of the rest of that spacetime taken at the point where(when) a given dimension is "stuck"), and thus externally observed "2D" entropy is just stuck in time, ie. a projection of, the "normal" 3D entropy of the black hole insides. Drawing some parallel with light coming out of deep gravitational well - the lightwave is stretching like the time dimension is getting "slower" until it stops in the case of black hole. The stopped dimension and an absence of the dimension - not much difference math- and observation-wise.