Thanks Nokinside! This is a great and easy to follow takedown of the concept on several dimensions (which I've chosen to summarize inline):

First, that making the internal device apparatus more complex is counter to the production of energy (you must put stuff in the way of the plasma that has to go fast) and it's also counter to the stability of the device (the plasma that's going fast hits the stuff you put in the way, and the neutrons you produce also hit the stuff you put in the way). Second, that more complex configurations don't in any known configuration actually trap plasma better (i.e. without escape vectors along field lines), and third, that the reactor-size problem comes down to physics of temperature gradients, not (mostly) of plasma containment.

Now, I have to wander a little bit down the path of rebutting common fusion concerns raised in sibling comments:

The link then mentions that tokamaks (powerful magnetic confinement) and stellarators (geometrically engineered plasma-self-confinement) are two existing designs that can manage not to leak plasma.

ITER, as seemingly everyone knows, is a tokamak big enough to potentially be net positive but with an absurd organizational cost and build time. Wendelstein 7-X is a big stellarator potentially able to give us good info on further stellarator designs (and has been a motivator for some cool industrial design advances).

I wish that more people on forums bemoaning ITER would learn about ARC at MIT, which is a very well-considered modernisation of the "big tokamak" design, with potentially-available high power superconductor magnets. MIT recently made a large push in favor of this, with op-eds and articles in major newspapers announcing large investment in an MIT-affiliated spinoff company by the Italian energy conglomerate ENI to pursue the initial risky magnet-design and then the routine tokamak construction after.

ARC is our best hope today, and ITER is a great long term fallback. Wendelstein is a great research tool, which may someday lead to a power production system. Then there's also the dozen-plus small startups or projects nestled in big orgs, which are mostly research-stage projects, and the whole ecosystem acts as a feedback loop for progress. Everyone's learning together.

Of course, even once (er, if) ARC hits net positive rapidly repeated pulses in a few years, there's a lot of issues with tritium and other industrialization and policy concerns (as mentioned elsewhere in this submission's comments) to figure out. But huge money will start pouring into fusion as soon as we have a system that "works", and right now it really seems like we might before 2025. That money will necessarily cause rapid progress on the industrial and engineering work, because that type of work is comparatively easy, and the upside will be both very real and yet also unimaginably high.

Fusion is not taking up all of our resources elsewhere, not by a long shot, so while there's even a thin sliver of a chance of it working out it is not reasonable to wholly stop pursuing it in favour of some other plan like all-solar+wind. And right now there is a heck of a lot more than a thin sliver of a chance!

...but, it seems Lockheed's effort would be a big surprise if it's the thing.