^There is zero evidence that what Prophet prayed for only 3 days was Tahajjud. The Hadith is clear people WERE praying Nawafil in Ramadan DURING Prophet's time, during Abu Bakr time too.
Allah's Apostle died and the people continued observing that , and it remained as it was during the Caliphate of Abu Bakr and in the early days of 'Umar's Caliphate."
And all what Omer ra did was to collect them in one congregation instead of small congregations. * A man praying alone or a man praying with a little group behind him. So, 'Umar said, 'In my opinion I would better collect these (people) under the leadership of one Qari *(Reciter) (i.e. let them pray in congregation!)'
Please look at my post again and answer my question that Umar did not pray the "tarawih" then I will respond to this question.