I don’t see any reason not to think that he was wrong.
We didn’t even discuss the dating of his “prophecies”. For example, the statement about Tyre was made in “the eleventh year, on the first day of the month,” (26:1). If, then, the prophecy against Egypt in chapter 29 was made in the 27th year, about sixteen years separated the two.
Ezekiel’s statements concerning the destruction of the surrounding nations were motivated by the fall of Jerusalem, which occurred in 587 B. C. He mentions this as the reason why Yahweh was pronouncing judgment against them (25:3-4, 6, 8; 26:2). Obviously, then, these doom’s-day prophecies had to have been made after the fall of Jerusalem in 587 B. C., and thus his prophecy against Egypt, which came 16 years later, could not have been made before 571 B. C. By then, Nebuchadnezzar’s siege of Tyre, which lasted from 585-572 B. C., was over, and Ezekiel would have known that his prediction had failed.
The admission of failure in 29:18-19 referred to Nebuchadnezzar’s siege of Tyre as a done deal, which of course by this time it would have been (as the dating by Ezekiel indicates). That being true, it necessarily follows that the book of Ezekiel could not have been written, at least not in its entirety, until after the siege of Tyre was over. This raises at least a few questions about Ezekiel completing his book after the events he had prophesied about.