You still have the cost of steam turbines and generators just like a coal/oil/gas power plant. The main cost savings is the fuel cost, which is a small but significant fraction of today's electric power cost.

There are theoretical proposals for direct conversion of electricity using the charged particles of certain fusion reactions (usually using Helium-3 mined from the moon) in different reactor designs but those are even further out than the toroidal magnetic confinement reactors (tokamaks, spherical tokamaks, and stellarators.)