When any’thing’ approaches the Planck length, it is being arranged in such a way that it is essentially in a ‘Bose-Einstein’ condensate arrangement and quantumly connected to every other bit of matter in the Universe. Since matter is nothing more than condensed energy (energy captured with a pinch of space and a whisp of time), why not consider black holes the enegine generating the expansion of spacetime?
God has given us enormous complexity from His most generous simplicity.