The majority of the team was cut in the first wave of Twitter layoffs on 4 November (wrote about this [1]) - when 50% of people were let go. By this time, most of them were working on Twitter's long form tweets, which feature was being tested with customers.
So this decision was indirectly made on the first week of the Twitter takeover. In the end, it was perhaps two people left from the old Revue team. Today, there's only the founder of Revue, who wrote this article, everyone else let go AFAIK.
What was very, very surprising to me is how, a month and a half later, Elon Musk replied to a question on how he's open to the idea of acquiring Substack [2]. But he just shut down Revue, which was exactly "Twitter's Substack" version with all the same features: newsletters, support for paid, plus first-class integration into Twitter that Substack does not have.
[1] https://blog.pragmaticengineer.com/cruel-changes-at-twitter