I'll ask another question here.
What 35mm slitting, perfing and spooling equipment will be operational in 2038 considering they have to be custom built and constantly maintained. This is not a specious question. If these machines are retired, there will be no 35mm film to feed any operational camera.
It is easy to slit and chop roll and sheet film. Perfing without defects and removal of the perf debris is not trivial.
You know, the depressing assumption throughout this entire thread is that our manufacturing abilities will have completely evaporated in 30 years' time...
If the LCD in my camera fails, could I produce a replacement LCD? No. But I could easily produce a functional equivalent using something like LEDs; it wouldn't necessarily be pretty, but I can guarantee you it would work. Hell, in 20 years I would be surprised if with the aid of an inkjet printer and electro-luminescent ink I couldn't produce you a replacement that was actually better than the original.
With advances - in FPGA technology in particular - that have already happened, I'd posit that actually even the custom logic components of an SLR would be within the capabilities of a homebrewer today.
As for the mechanical components of a camera; of course they are all replaceable. The fact there are still horologists - both professional and amateur - keeping clocks running stands testament to that.
Oh, and I've seen the 'small' 35mm punching, edge-mark-exposing and finishing machines at the Ilford factory. Could I make one myself? No, but I bet your bottom dollar I know a man who can. Has lathe, doesn't travel much, but if you think a 35mm perfing machine is irreplaceable technology I'd like to introduce you to him or the many, many people keeping vintage computer gear - including card punches, readers, tape handling mechanisms, printers, etc. etc. - running.
Speaking of which, I have a 30-odd year old DEC PDP-11 running in my understairs cupboard, which suggests the fears of anything electrical evaporating once it passes a certain date may be overblown

.
Any of this stuff can be kept running provided there is someone out there with the will to do it.