I totally follow. There are zero sources which allow us to not eat shalishudis.
The Mogen Avraham is not saying we can skip shalishudis. Not even on erev Pesach, since we hold we can be yotzei b’dieved with peiros. He is bringing the Rashbi as an opinion that peiros aren’t sufficient, but isn’t paskening that way for erev Pesach.