coverman, you could say that about almost anything that people collect!
I don't think any of us actually "need" a C5 (or more than one!)
At Ardingly, there were a number of people surprised to see that c5alive existed - they didn't think anyone would be interested in Sinclair c5's (some were rude enough to say we shouldn't bother
).
Along with what Mike says, if it exists then there will be someone who will be fascinated by it. The invalid carriage could even be a nice little earner for renting out to film sets etc