It isn't just 'Made in the USA' that is an obstacle, though it is a big one, it is all the testing, support and integration that would be necessary to make it a viable weapon system on the LCS. Installing and testing the necessary radars, making sure it and the missiles meet US specs and that it doesn't interfere with other US systems (emissions control, inadvertent jamming due to frequency overlap, etc) are just a few of the things that would have to be checked out. Then there is the support, do we manufacture the missiles or rely on Sweden to make sure we get supplied with them? Can we do upgrades on our own?
There is good reason we procure weapons the way we do, we often actually use them operationally when much of the world never does. Many countries buy weapon systems without taking everything into consideration and they are often unsustainable in a conflict lasting more than a few days or at worst are nothing but showpieces. You find this often in the Middle East but it is the same story all over the world. That is one reason US FMS sales, while very expensive and often restrictive in some aspects, is appealing to many countries. We don't just sell them the weapon system, a few manuals and which them luck but we try and sell a weapon system that can be maintained and used for as long as the country wants it.
If you want a good example of two countries with completely different train and equip philosophies you can do little better than to study the Falklands War. Even with an air force that was much bigger than the UK forces in the region and a military that was well-equipped on paper the Argentinians were soundly defeated by the Brits.
