Regarding reloadable launchers:
You need to make - and survive - 3 attack runs to break even with box launches. You need additional support capability (colliers or missile stockpiles).
This is before point defence, which greatly favours one sufficient strike over several small ones. Admittedly, the enemy may be more limited by number of salvos than number of missiles here.
Again, you insist on a marginal capability that may never become relevant, and reduce the efficacy for the simple and most likely scenario to a rather small fraction of what it could be. If you bring enough of an ammo train to support this, you may as well bring a dedicated strike fighter and only give the Javelin capability that can be had in a weight-efficient manner.