ITER is supposed to get break-even. Plasma experiments can better be done at smaller, much cheaper facilities (many of which already exist).
ITER, as of 2006, was supposed to be followed almost immediately by DEMO, a power plant capable of producing electricity in 2033. But now ITER is so delayed that it's almost irrelevant. In order to address climate change, we'll have to have transitioned to, say, solar and storage before the 2050s when DEMO might be built, or we'll be stuck with terrible climate consequences.
It's just insane how bad it has been. ITER is so badly delayed that it's almost certainly not going to be a key player in fighting climate change.
As for breakeven: no plasma physicist I’ve talked to see it as some amazing barrier. It is what it’s always been: a publicity thing. It gets people excited so laypeople can point and say “See! It works!” without having to dive deep into physics and economics. The real physics goals of ITER are in testing models when pushed outside of previously measured parameters. You can’t just spend $50 billion on a reactor and hope it works. That’s why increasingly large and expensive science machines are necessary. Once a design is complete you don’t need diagnostics and scientists. You just need a tritium processing facility, some HTS coils, some vessels, and some plasma heaters.
You're conflating ITER with fusion power in general. There're at least half a dozen competing approaches to fusion power with several orders of magnitude lower funding. Several of them are probably more promising than ITER, but ITER is primarily a political project, and only secondarily (at best) a physics project.
Fusion is a technology that's being pursued because it was being pursued, not because it's particularly attractive from a practical point of view.
This is not true. DEMO will not be able to breed Tritium.
Without tritium breeding, there will be no self-suffiency in term of fuel. You can't filter Tritium from sea water because it is not there - it is unstable. There is no fusion experiment which could achieve a Deuterium-Deuterium fusion within the next decades, the required densities are many orders of magnitudes away.
You can generate Deuterium by electrolysis and isotope separation of water, but to day, Tritium can only be produced in heavy-water generators. Which exist only a few in the world, and which are powered by uranium.
In theory, yes, it could be possible to breed tritium within a fusion reactor. But this is as theoretical as somebody in the 17th century saying that you could adapt a steam engine to flap wings and make it just a bit lighter to get a flying machine which could carry a few hundred people with near speed of sound across the Atlantic, at once.
DEMO not only will breed tritium, it will not be feasible without tritium breeding. Otherwise, it would not be able to operate, as it will run out of DT fuel. Even getting enough tritium to start DEMO operations will be difficult, as there will be little left after ITER is done. The primary source of tritium, heavy water power reactors, will not long survive, and even all of those would not provide enough tritium for DEMO operation without DEMO being able to make its own tritium.
The need for breeding to work at DEMO means there's going to have to be an intermediate reactor, a Fusion Nuclear Science Facility, between ITER and DEMO to firm up blanket engineering.
I don't think this gets talked about much because, frankly, those in power in the fusion community will be retired by then.
But is that the fault of the scientists and engineers working on it? Or of the politicians writing the checks (and their apathy and/or conflicts of interest)?
I imagine Peter Venkman in Ghostbusters saying this to the Columbia dean as their lab is being disassembled and they are being fired.
Also, ITER is a plasma physics experiment. It is being made to learn about plasma behavior. It isn’t going to fail or somehow not produce useful results before DT or high Q campaigns. A fusion reactor does not fall out of the sky. Was the V2 a failure because all it did was eat up a bunch of money and blow up a bunch of expensive equipment? No. The knowledge costs money. Tangible things are laughably low value by comparison.