Does Mark 9:1 set a false date for the second coming?

Here are some comments I posted in the YouTube thread on early Christian eschatology that I linked earlier:

The point about not tasting death in Mark 9:1 is that something normally not experienced in this life will be. The not tasting death is therefore relevant regardless of whether the event in question happens six minutes, six days, or six decades later. The issue is the growth of the kingdom of God in this life, such as in its power (a theme we also see elsewhere, such as in the passages cited by Bram, 1 Corinthians 4:20, the reference to the power associated with the Mount of Transfiguration in 2 Peter 1:16-18, etc.). Not only does Bram's reading of Mark 9 make sense in the abstract, but it's also widely corroborated by other passages, including the specific reference to power in the discussion of the Mount of Transfiguration in 2 Peter. And it's unlikely to be a coincidence that an account of the Mount of Transfiguration immediately follows Jesus' comments in every one of the Synoptics. It looks like Bram's interpretation goes back to the time of the Synoptics and 2 Peter.

D.A. Carson has argued for a chiasm in Matthew 16:24-28, which is Matthew's parallel to the passage in question in Mark (The Expositor's Bible Commentary, Revised Edition, Vol. 9: Matthew & Mark [Grand Rapids, Michigan: Zondervan, 2010], 434). He points out that verses 24 and 28 refer to events of the immediate future prior to the second coming, whereas verses 25 and 27 refer to "reward and punishment at the Parousia". He characterizes verse 26 as the central one in the chiasm, involving the "central weighing of values". It follows that the passage about not tasting death isn't about the second coming.

Furthermore, Matthew 16:28, Mark 9:1, and Luke 9:27 all use significantly different language than what's used in the verse just before. There's a shift from the glory of the Father and angels to a discussion of the kingdom. Why is such different language used if the same event is in view? There could be such different language used to refer to the same event, but the difference makes more sense if different events are in mind. So, that change in language (from 8:38 to 9:1 in Mark's gospel) makes more sense under a view like Bram's.

And your appeal to "the explicit statement" in Mark 13:30 fails to interact with multiple lines of evidence Bram mentioned in the video. The "all these things" of verse 30 is most naturally taken as referring to the signs akin to the ripening of a fig tree mentioned in verse 29, which means it doesn't include the second coming itself. And verse 32 denies that a date can be set, so an interpretation of verse 30 (or 9:1) that has Jesus setting a date makes less sense accordingly.

Then there are the problems with your view in the sources outside Mark's gospel, which Bram and I have discussed at length. Why do the early Christians not show the sort of concern for addressing a failed prophecy that we'd expect them to exhibit if there had been such a failed prophecy? Why do the early heretical, Jewish, and pagan sources seem unaware of such a failed prophecy? Why are there early references to how the normal course of history could go on past Jesus' generation, such as in Ephesians 6:1-3?