It feels like fusion energy is perpetually 50 years away.
Early designs for ITER where for a larger device that would have actually produced electricity though not cheaply enough to be economically viable, but it got scaled way down.
HTSCs weren't usable when it was designed, and have only just become usable in the last 5 years or so but they are a fundamentally different material. You don't just drop them into a large, incredibly complex machine that depends on it's integrated magnetic containment system: you are functionally building a new device.
If you can ITER, then you don't get a refund on spent dollars. You get a loss. And then you get to start another 30 year project to maybe build a new vacuum vessel, which you have to do because you still haven't actually tested plasma stability.
"But but MIT skunkworks!"...yeah. It's still going along, and they haven't suddenly churned out a functioning reactor based on HTSCs because oh look, whatever the advantages they're a new material with different properties, manufacturing and handling behaviors all of which need to be developed, measured and inspected before you can use them effectively in a fusion device. If they look good then great: they can be used to make DEMO, the ITER-successor commercial powerplant prototype, cheaper and more powerful.