I think ships could be a much different story, much like the T-6 being made from scratch here only using the design with American mods and a completely free license to do what we want while most of the others you cite had much more serious limitations from mere assembly to licensing issues.
All that being said, it is up to the Navy to ask/contract for that sort of platform and for our shipbuilders to actually build them. It isn't like the LCS or Zumwalts sprouted out of nowhere or shipbuilder's fervent minds, we can thank the Navy for those bright ideas and everyone for its wonderful execution.
Pulling in a foreign design really wouldn't solve our problems, and would bring with it entirely new ones. The Europeans also have different accounting for their costs, which also lets them run lower numbers than we do. The Japanese and ROKs, being #2 and #3 shipbuilders on the planet behind the PRC, are probably always going to kick other developed nation's asses on construction cost and efficiency. Since we're not ever going to be allowed to buy ships actually BUILT overseas, buying foreign wouldn't help us.
As you noted, the LCS problems didn't come out of our shipbuilders...we got exactly what we asked for. Same problems as JSF, except the tech development for LCS just isn't a high enough priority for funding, and Zumwalt basically doesn't even make sense in terms of what it was originally thought up to do.
When the requirements are that hosed up, the design side doesn't even have a chance.
It's not like we can't design or build ships. We run into trouble when we try to get "transformational" with immature technology.
IF the current fleet (even brought back to full health with a healthy injection of maintenance) is insufficient for the strategy, and not enough shipbuilding funds are available to execute the preferred strategy - are there any suggestions?
Depends. Like I was saying...we haven't really articulated the desired end mix of capacity/capability.
What is the desired end state? The future Fleet of 20-30 years is what we should be looking to build towards. Shipbuilding takes a LONG time, and that's just with known designs.
The current shipbuilding strategy will probably keep us on rough trajectory for maintaining a rough status quo while we figure out the long term game.
If we can't fund that, there aren't any magic solutions that get us there on thin air...we'd need to go back and re-scope what the sustainable end state needs to be to fit the available funding.
Now if we are just looking to temporarily solve problems in the nearer term, then yeah, one off solutions like modernization or arming ships differently (see concepts to arm either the EPF/HSV transports or the LPDs) start to make sense. Or even just shit out a bunch of smaller frigates/corvette missile sponges if you just need to hit a capacity target for Fleet presence.