The Shvuos are from Shlomo Hamelech, as I quoted from the Rambam. The explanation is from the Amoraim, after the Churban Bayis Sheini. The problem is Ad Shetechpatz. Navi or not, the issue is going up before the Zman Geula. All the Jews knew that the Galus Bavel was over. There were Divrei Nevua about that long before. Ezra is considered a Navi, and whether or not he is Malachi, Malachi was around to be asked. The Jews went, or were supposed to go, because it was a Zman Geula. As per the Rambam, and anyone else who wrote about Moshiach, the Zman Geula has not come yet.
So, when exactly were the Shvuos valid? Until when? Where is this visible or alluded to in that Gemara?