I'm quite willing to believe that Earth would never have made amicable first contact with Vulcans if not for the Borg help of bringing 24th century starship engineers back in time to get Cochrane's warpship built and launched. It would just be an iterative process: the first shanghaied engineers would meet a pile of junk that could never fly, but would do their best to improve on matters, and each would contribute to the legend of Cochrane having built a working warpship, so that each successive shanghaiee would have a better idea of what that working warpship looked like. Essentially, when LaForge went back to the past, he was expecting to find a ship designed by LaForge, only he thought Cochrane had done the work. He found exactly that, since the previous iteration of the ship had indeed been done by a past version of him, so he came perfectly equipped to turn a piece of unworkable junk into a LaForge style starship; history books told him what adjustments he needed to make! The Borg bombardment of the silo would be there just to help camouflage the fact that the original warp rig was always just random junk thrown together by a madman, by making it look like this was a ship historically known to be workable, and merely damaged by an attack.
The last hijacking of LaForge (the one we saw) would just put the finishing touches to the iterative process which was nearly complete already and had almost produced the kind of UFP the Borg wanted...
Timo Saloniemi