It's an incentives problem. Nearly all of the world's power is generated by spinning a turbine with steam, so, we have a direct, actionable, incentive to make that process as efficient as possible, and we have indeed done this and continue to do this. Modern steam turbines are wildly efficient.
That doesn't mean that they are the only thing that can be efficient, just that they're the current best option, and, any other option is going to have to show immense promise in order to get the funding to catch up to where we are now with steam.
The only thing on my radar that bypasses steam entirely is what Helion Energy is doing up in washington with their experimental fusion devices. The basic idea being that you're using a pulsed fusion reaction and intentionally not containing it, instead using the energy produced to push back on the magnetic containment and generate power. No idea if it'll work out to be viable, but it at least makes sense on paper.
You're correct. The design of nuclear reactors was intended from the beginning to replace steam generation, with the goal of not needed to redesign the entire generating plant and take advantage of the known tech as much as was reasonable. There were ideas around for just replacing existing coal/gas/whatever with reactors, to get the most value out of the capital expended on the plant. There are still studies around retrofitting retired coal generation with nuclear reactors.
Just like steam tractors were designed to replace horses.
Which is a fascinating factoid really, because the farm tooling was designed to run at a certain speed (maybe not intentionally, but, over time, that's the design criteria regardless), so the tractors were designed to run about as fast as a horse so all existing tooling could be retained.
It wasn't until much later that tooling was redesigned to work faster.
That doesn't mean that they are the only thing that can be efficient, just that they're the current best option, and, any other option is going to have to show immense promise in order to get the funding to catch up to where we are now with steam.
The only thing on my radar that bypasses steam entirely is what Helion Energy is doing up in washington with their experimental fusion devices. The basic idea being that you're using a pulsed fusion reaction and intentionally not containing it, instead using the energy produced to push back on the magnetic containment and generate power. No idea if it'll work out to be viable, but it at least makes sense on paper.