I have mixed feelings about this. There are many cameras I'd have loved to own, but never bought.
Pentax LX for example, or Olympus OM1, were dream cameras for me. I may still, one day, get one just for fun. Even if in the end they "lost", they are still dream cameras.
On the other hand, more than "Canon's adoption of plastic", it's "Canon's adoption of unreliable shutters" that helped me forget about SLRs. I had a T90, best design ever for an SLR if you trust me, but had to get the shutter fixed once, then got it fail again after a few years. Got an EOS3, which was quite as good as the T90 (but for twice the weight. The only advanced feature was the AF, but to get the same shooting speed I needed the booster), and developed the same shutter issue.... So I'll never buy a Canon SLR, except for an A series of a F1...