Is that relevant? The economics of nuclear plants doesn't have anything to do with efficiency as far as I'm aware, the fuel costs are relatively negligible. They can afford to be horribly inefficient if they can get economies of scale producing the plant. So you can use inefficient turbines and have bad neutron economy and it wouldn't change the economics by anything in particular.

You'd also probably find similar issues with diesel generators, but small diesel generators do roaring trade and have great commercial applications.

Cost is not only relevant, it's paramount. Efficiency is only important insofar as it affects overall cost.

Diesel generators have the advantage of being very cheap -- an order of magnitude cheaper than NPPs per unit power output -- and of having much of their total cost being fuel cost, so they can operate at lower capacity factor. But even so, we don't see large power plants composed of arrays of diesel microgenerators.

(The solution for current higher capacity factor diesel users, like say remote operation at mines, would be to supplement them with renewables and storage to reduce fuel costs. This is already happening.)

A significant problem with any small power plant is fixed costs. A 1 MW(e) plant (Antares is said to be between 100 kW(e) and 1 MW(e)) making power at 90% capacity factor and selling at $0.05/kWh will gross about $400K/year. A single full time employee, like a security guard, will cost a good chunk of that.