If God is able to (in ways which we see not, and know so little of... if anything) guide or direct or steer the course of all creation, then perhaps this alone is sufficient for Him to declare the end from the beginning.
2 Kings 19:25a
Hast thou not heard long ago how I have done it, and of ancient times
that I have formed it? now have I brought it to pass...
Isaiah 46:11
Calling a ravenous bird from the east, the man that executeth my
counsel from a far country: yea, I have spoken it, I will also bring
it to pass; I have purposed it, I will also do it.
Jeremiah 18:6
O house of Israel, cannot I do with you as this potter? saith the
LORD. Behold, as the clay is in the potter's hand, so are ye in mine
hand, O house of Israel.
The point of this being (as viewed from any position or perspective), it is absolutely impossible for there ever to be more than one with the power and ability to do this. And, given the presentation of this simple and logical impossibility, Isaiah (speaking for God) emphasizes the absurdity in Israel's idolatry. He asks them before:
Isaiah 46:6
To whom will ye liken me, and make me equal, and compare me, that we
may be like?
Furthermore, Israel is called out like this again on their treachery and rebellious idolatry in worshipping other gods, thinking there is any other than God that can do this. Driving the point home even deeper, God makes the statement here that what he declares, can be created now. Thus making it impossible for Isael (or any of its idolatrous gods) to have known about it before.
Isaiah 48:1-7
[1] Hear ye this, O house of Jacob, which are called by the name of
Israel, and are come forth out of the waters of Judah, which swear by
the name of the LORD, and make mention of the God of Israel, but not
in truth, nor in righteousness. [2] For they call themselves of the
holy city, and stay themselves upon the God of Israel; The LORD of
hosts is his name. [3] I have declared the former things from the
beginning; and they went forth out of my mouth, and I shewed them; I
did them suddenly, and they came to pass. [4] Because I knew that thou
art obstinate, and thy neck is an iron sinew, and thy brow brass; [5]
I have even from the beginning declared it to thee; before it came to
pass I shewed it thee: lest thou shouldest say, Mine idol hath done
them, and my graven image, and my molten image, hath commanded them.
[6] Thou hast heard, see all this; and will not ye declare it? I have
shewed thee new things from this time, even hidden things, and thou
didst not know them. [7] They are created now, and not from the
beginning; even before the day when thou heardest them not; lest thou
shouldest say, Behold, I knew them.
Thus, it appears that God's unique ability to guide, direct, steer or create whatever is needed or necessary to achieve "the end" is intended to further convict Israel of their transgression of idolatry, and failure to believe whatever "end" God has already revealed (and/or continues to reveal) to them.