I had some time to look up the sicha about how we finished avodas habirurim. The rebbe brings from Torah or and toras chayim that already Yaakov avinu finished all the birurim, and was ready for the geulah,
so your kashe is why moshiach didn’t come then and it’s on Torah or and toras chayim and many other places.
The rebbe explaina there the difference between then and now see there.
Now Yaakov avinu after the thought he finished avodas habirurim he did the avoda of העלאת מ”נ see Torah or.
Don’t ask kashas on anything before you learn the whole sugya!!!