> I'm not convinced that'll ever happen due to one massive problem: energy loss from high-energy neutrons

That's just one of many massive problems? You touched on the reason for this:

> Stars deal with this by being massive, having fusion happen in the core ... and gravity, none of which is applicable to a fusion reactor.

As a result of this, we actually have no good reason to believe that commercially viable fusion power could ever be possible.

While we can create conditions comparable in relevant ways to the core of a star, it's extremely uneconomic to do so, for obvious reasons.

And we haven't even achieved the scientific breakeven point for a sustained reaction, let alone one that remotely approaches being viable from an engineering or economic perspective.

Neutron energy loss would be a good problem to have, because it'd mean we're much further along than we are now. The fact that, after half a century and enormous expenditures, we haven't even reached the point where neutron energy loss is the main problem, gives an idea of just how unrealistic this all is.