Industrial grade steam is still widely used and that probably won't ever change except to move from steam to supercritical CO2 and then only for power production. Most steam is used to do other things that are critically important to modern society. The biggest one is to make fertilizer without which we can't feed most of the planet. Your understanding of how industry works is fundamentally flawed.
You can slow down those particles against an electric field and harvest the energy as electricity directly. No steam turbine. No Carnot limit.
https://en.wikipedia.org/wiki/Nuclear_fusion#Important_react...
The lowest-threshold nuclear fusion reactions (deuterium–tritium (D–T) fusion, used by ITER, Commonwealth Fusion Systems) release up to 80% of their energy in the form of neutrons. These designs have to convert energy of the neutrons to electricity, indirectly using heat.
Since it is simpler to convert the energy of charged particles into electrical power than it is to convert energy from uncharged particles, an aneutronic reaction would be attractive for power systems. However, the conditions required to harness aneutronic fusion are much more extreme than those required for deuterium–tritium (D–T) fusion.