Steve, I suppose your theory is akin to collecting milk bottles.
Interesting to look at, but no longer used. Or as you state, museum pieces.
The question at this point is, are milk bottles in short supply compared to the number of collectors looking for them? If yes, they likely retain or increase in value.
It all boils down to collector interest.
Once the generation that remembers using a ticket to gain admission to an event is gone, will anyone care?
In the case of baseball ticket collecting, I suppose it depends on baseball's overall draw as a collecting hobby. I guess we will see...
By the way, you do need to get those kids off the lawn LOL