Kozov,
I read your source and my explanation is in line with it if you don’t take it too literally (the lasid lovo thing was only meant to clarify that we were discussing Yimos HaMishaich when the normal rules of halacha and nature will apply).
There is no way we can say with certainty what the future Sanhedrin HaGadol will pasken on any given issue. Just because Bais Shammai were sharper doesn’t mean they were always right (or else we would pasken like them now). Rather on every given issue the future Sanhedrin will render a psak (and paskening like Bais Shammai will once again be on the table).