I agree this is an interesting question. While many of these recent vintage film SLR's suffer from too much plastic, etc. they are often in overall better condition than better made vintage SLR's, many of which now need servicing. The later day SLR's also usually have working TTL meters that use modern batteries. For this reason they may be useful for those experimenting with film photography for the first time.
I've found the Cosina made mechanical shuttered SLR's of this genre such as the OM-2000 and Nikon FM10 to be fairly decent and reliable SLR's (for instance).
I don't know much about the late Contax era SLR's, but I did see one about 20 years old with build quality that really impressed me, especially the brightness of the finder. The Contax series mostly had electronic shutters though, which I avoid, but I think there was a mechanical shuttered version (S2 or something like that).
I think all 35mm film SLR's will eventually appreciate in value unless someone starts up production of reasonably priced models again -- same for other formats of film cameras in fact - we can only hope!
Canon L1, Leotax S, Bessa R2C, Konica Autoreflex, Canon FX, Pentax Spotmatic, Minolta SRT-101, Nikon F, Exakta VX, Miranda Automex II, Leotax K3, Yashica Mat LM, Leotax S, Pen FT, Rollei 35S, Ricoh Singlex TLS, Kowa Six, Pentax K1000, Canonflex, Praktina, Voigtlander R2C