I can't follow your reasoning. The OT text is quoted in Hebrews and the "little while" is expected from the point of view of the writer of Hebrews. Why couldn't it be a reference to something about to happen, or in process of happening, when he wrote the letter?
Heb. 8:13 says, "In that he saith, A new covenant, he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away."
He was looking forward to the removal of the old economy (the priesthood and sacrifices, to which the Hebrews were tempted to return, and which were superseded by the priesthood and sacrifice of Christ). In chap. 9 he speaks of the time of reformation of the O.T. ceremonies connected with the law. In chap. 12 he has just contrasted Sinai and Sion as two different economies. It makes perfect sense that the shaking is in terms of the old economy and that the new economy of the gospel will remain.
Yet, with John Owen, we should also see the continuing significance of this. He writes,
"We shall yet further observe, that although the removal of Mosaical worship and the old church-state be principally intended, which was effected at the coming of Christ, and the promulgation of the gospel from heaven by him, yet all other oppositions unto him and his kingdom are included therein; not only those that then were, but all that should ensue unto the end of the world. The “things that cannot be moved,” are to remain and be established against all opposition whatever. Wherefore, as the heavens and the earth of the idolatrous world were of old shaken and removed, so shall those also of the antichristian world, which at present in many places seem to prevail. All things must give way, whatever may be comprised in the names of heaven and earth here below, unto the gospel, and the kingdom of Christ therein. For if God made way for it by the removal of his own institutions, which he appointed for a season, what else shall hinder its establishment and progress unto the end?"