We sit here and gawk, but this is often times how it goes.
I remember back in the day owning a 1989 BMW M3 (E30 M3). I bought it for 10k from a forum, and it was in pristine condition. Sure, it was a good looking car and it was fun to drive when I was younger, but it was by no means insanely fast or anything special, just a really cool car.
Well, I wish I had held onto it, because nowadays they sell for upwards of 40k all day long. In fact, Haggerty has one in "good" condition going for 60k, and a pristine example going for 120k.
My point is that all "collector" vehicles usually start out as something where no one really sees the insane value, but somehow they keep getting driven up in price, because people are willing to pay it.
The issue with TJs however (that I think will prevent this), is that there was so many of them made, that it's not really a "rare" vehicle.
The E30 M3 on the other hand was only made in small numbers (10,000 I believe), so the amount of them that are still around these days aren't as many.
Who knows, maybe one day the TJ will get there (I hope it does), but in the meantime, you'd be stupid to pay 45k for a vehicle that is just over a decade old.