I'm not talking about plausible now, but plausible some day, as a reply to your "It seem very doubtful ... any time soon or necessarily ever". The sections being repaired could be offline. "Self-repair" doesn't assume repair within volume of an existing/operating structure, it could be all cleared out and rebuilt anew, for example. That it's done more or less automatically is the economic requirement. Any other methods of relatively cheap and fast production, assembly and recycling will work too.
Ah ok. That's a lot more plausible. There's still the issue that once you have cheap solar the resources it takes to make fusion power will simply cost so much more as to likely not be worth it. But if it could be substantially more efficient than straight fission then maybe it would get used for stuff not directly on Earth if/when we have large installations that aren't the inner solar system.
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