So i'm wondering if all these big institutions are actually using ethereum network, or are they just using private forks and such? If so, then ethereum is no different than ripple
Obviously now they are in the research / development period. Eventually some will use private forks, some will use private interoperable with the public one, and some will use public. It's impossible to know how it will be used now because these companies don't even know it themselves.
Public eth will benefit even from those who will use private forks, because EEA is formed to develop a standard ethereum and not a specific product, so any development will benefit the public chain aswell.