Look up sophistry or cognitive dissonance when you have a chance, as you either or have resorted to misconstruing the argument or you have have succeeded in misunderstanding it.
No, it does not follow that since the Sanhedrin was an organized authority but was wrong, then Catholic Church must be wrong since it is an organized hierarchy, which is what you conveniently construed the argument to be.
Instead, it does follow that if an infallible magisterium is essential for the discernment of what is of God, then since then it is contrary to how the NT church began, as there was no infallible magisterium to tell them what was Scripture or the Messiah.
And in fact it began in dissent from those who sat in the seat of Moses, while under the Catholic model the historical magisterium and steward of Scripture dissent is disallowed.
Thus the shared similarity of being an organized authority does not make the RC mag. wrong, but the very premise that ensured perpetual magisterial infallibility is essential is the issue, due to the posters questions. Which should have been obvious.
If want to compare reasons for the Rc mag. being infallible versus the OT mag then go ahead.
It might be good to observe that in spite of Jewish claims to infallibility, and the identical claims of infallibility by the Roman church, the ecclesiastical branch has never been very good at maintaining pure doctrine - It has ever been the prophet who is raised up with the purpose of straightening them boys out.
Of course, they don't like being upbraided much, so in righteous indignation, they kill the prophet, and eventually YHWH quits sending prophets altogether. A few questions arise thereby:
Foremost: Where have all the prophets gone (long time passing)
If Israel was punished for every prophet from Abel to Zacharias, I wonder who will catch the grief for all the prophets since Zacharias?
Lastly, when the prophets do finally again appear, they arrive as a prophet of doom. Who in our day will recognize an Ezekiel, laying naked in the streets, playing with sandcastles and cooking on poop?
AUTHORITAY!!! It is a caution.