First of all, it needs to be understood that there is a difference between the telic and the ecbatic when it comes to scriptures being fulfilled. When it says “that it might be fulfilled” that does not mean that this specific event was prophesied of by Isaiah, but only that such a scripture is fulfilled by this specific event through applicability or similarity. When a scripture is in the telic sense it refers to a specific prophecy, but when it is used in the ecbatic sense it refers to events that fulfill passages through parallelism.
Albert Barnes said, “Might be fulfilled – That the same effect should occur which occurred in the time of Isaiah. This does not mean that the Pharisees rejected Christ in order that the prophecy of Isaiah should be fulfilled, but that by their rejection of him the same thing had occurred which took place in the time of Isaiah.”