In terms of thermodynamics, the gearing ratio is irrelevant when discussing the energy density of the 'working fluid' since the working fluid is that which drives the turbine.
In terms of thermodynamics the gear ratio is everything to do with the energy density of the working fluid in the turbine. It's the gear ratio that determines the energy density of the working fluid in the turbine by multiplying the tidal head by the gear ratio to produce the turbine head.
If you are only interested in the relationship between the turbine and the working fluid in the turbine you are confusing fluid dynamics with thermodynamics.
Interesting, then perhaps you would care to provide a reference to support your assertion?
Why don't you simply explain why the gearing ratio and the energy density of the turbine working fluid are irrelevant in terms of thermodynamics? Should we assume that you have invented a system that is is exempt from the laws of thermodynamics? That's what your statement implies.
I didn't think you would be able to provide a reference for your assertion but rather than concede the point you choose to paraphrase? Unless we can agree on the meaning of the thermodynamic terms the discussion will continue to be an argument in semantics i.e., utterly pointless.