I think that at the current rate, the DOD will eventually own one aircraft that the USAF will get Monday through Thursday, the Navy onFriday and Saturday, while the Army and Marines share alternating Sundays.
The CH-53K is definitely the heavy-lift helo of tomorrow. It's a big improvement, but an evolutionary one, over the current platform. The day after tomorrow, who knows? I tend to think that we're in a crisis, "Oh crap, we're wearing out 53s, what are we going to do?" mode. The current pace of operations and budgets is not going to continue, and when it stops, the Corps might find that it would have been better off giving a naval character to a joint program, e.g. the JHL, than a single-service solution when the chopping block is pulled out. Plus, as part of the JHL process, the Army has solicited high-speed solutions--200 knots+, that will mesh better with the tiltrotor side of the house that is coming online (like it or not).
This isn't to say I'm AGAINST the 53K. I just look at it and wonder whether we're just trading up to next year's model, when we really need a whole new platform. Just like the Yankee/Zulu, which were also supposed to be easy to build, but weren't.