I'm surprised no one has gone the pressure-fed route in a big way. OTRAG, Sea Dragon. Not counting any microlaunchers
The idea of the Big Dumb Booster was keen when turbopumps, ullage motors etc were prohibitively expensive but new manufacturing processes, or just doing what Electron is doing and going the electric motor route is making the point moot. I used to think someone would try it. I seem to remember that Beale was going for that, but now it seems like a dead end. Fastrac may well have been one of the most important NASA programs, in terms of the effects its had on engine manufacturing going forward. The people involved don't get much credit. Out of X-33, X-34, VentureStar, X-37, etc, the big experiments of the 90s, I would say the two things that have changed spaceflight the most are Delta Clipper X and Fastrac
In my opinion
In terms of who else will get crewed access to space: I think they'll buy seats on commercial providers. There just isn't a justification for designing your own hsf vehicle now when you can buy one from Boeing, SpaceX, or Sierra Nevada.
ESA has the reentry vehicle tech with ARD, the service module tech and docking tech with ATV, as well as all the lessons learned from Hermes. They could have a manned program quickly if they had a need, the will and the money, but there just hasn't been a point. In any case Orion will be using an ESA service module, so the argument could be made Europe will have the next space agency to send humans to space, since it will be a shared program.
Japan could also develop its tech from HTV experience, as well as from its experimental RTV craft, and the HopeX program into something quickly, but like India, this would just be a prestige program A vehicle with nowhere to go.