Yes it sounds like one of those jobs thats not worth the risk/effort for what people are willing to pay. My dad uses someone that rewinds transformers but thats not a fine wire, fiddly job on tweeters.
I would love someone to set up a Royd driver refurbishment process (even just doping them) at a reasonable price but its not going to happen. I realise thats its not easy or straightforward. Just tooling up for that process vs the demand would rule it out.
I had a guy make some Coniston foam grilles. The price was so reasonable that Im not sure how he made any money on the deal. he seemed a low volume operator so I wondered if it was even worth his while
These are the sort of jobs I know I would cock up despite my best efforts so If nobody else will do it Im stuffed.