I think you will find the term comes more from the fact that these are made of tin rather than the general wood and fabric of earlier aircraft, add in the fact that they are relatively easy to fly so what is inside the tin can can be fairly mediocre and you get the term!
Yes, definitely, makes a lot of sense with regards to the term itself.
But I have heard it used by many people to mean those planes that are purposefully run into the ground for a quick profit. Which coincidentally happens to also be club planes which are easy to fly, generally made of metal, and often flown by people with little/less experience (wether that be due to instruction, ability, number of hours or otherwise).