It would be possible, it seems, for Spatial to order a batch of correctly modified M3 Sapphire tweeters and offer them for sale to owners.
These tweeters have proven somewhat fragile, but they are a drop-in, no solder replacement.
I know Pass Labs has bins of out-of-production transistors going back more than a decade so they can support owners of their out-of-production products. It's the kind of conscientiousness that attracts customers to a business and builds long-term loyalty.