Plus we have a hard time conceiving of what it would be like to always be in a state of maximal, beyond-orgasmic pleasure.

When I imagine it I cannot help but let a little bit of revulsion, fear, and emptiness creep into the feeling - which of course would not be actually be there. This invalidates the whole thought experiment to me, because it's clear I'm unable to perform it correctly, and I doubt I'm uncommon in that regard.