We used to make sills for S14s but demand wasnt enough to keep doing it, I think we all know what the big difference is with TVRs as well
TR6s may have been shitheaps waiting to be scrapped but there were masses of them, theres still twice as many TR6s taxed as there are 200SXs remaining in total and thats before you get onto your GT6's, Spitfires Heralds and the rest. And they probably wont have lost a lot of their demographic to Facebook either.
Parts cars are the same problem as whole cars in that you need somewhere to keep them, when a lockup rents for £60 a month round here its just not worth it
Would love to be able to do it but the volume youd need isnt there globally IMO, never mind in the UK