The economics don't work only when compared to the modern alternative. The economics of a grindstone attached to a waterwheel don't work today but they did historically. A steam engine with low power output could still have been extremely useful in the right context despite not being up to the more strenuous tasks of historical variants.
Agreed, there's a lower bound set by the other available tech. I didn't do the best job articulating there. In the context of the thread my objection is that the economics of the finished product aren't the issue.
The problem is arriving at working knowledge of the tech in the first place. But that's clearly not a logical impossibility, merely expensive and dependent on lots of surrounding factors.
The obsession of a single rich elite, not economics, is precisely how much of early chemistry came to be.
