I use creams exclusively but have never had a problem with my brushes going hydrophobic (water repellant). I rinse thoroughly following each shave and my water is neither extremely hard nor soft.

Under the FWIW category, I too do not see the need for an extended submersion soak of a brush. If your beard is said to be saturated after a minute or two of applying water, what would make one think that badger or boar hair is much different?

Just another data point,
Ed