I've only had a handful of pins and they are generally getting increasingly newer and more expensive. First was a $3k Hook that needed work, then sold that to get a RCT from a friend and had that for a couple years to get a HUO Deadpool Pro that I got an awesome deal on and love it - that will be a cold dead fingers sale. I got a old Bally from a neighbor that was either going to be sold to me for cheap or put in the trash, it was in rough shape. I fixed it up, cleaned it up, got it working and sold it for triple. I then got a used, but awesomely updated/maintained WPT, have had it for a couple years. But now I am on the neverending 'in line for' NIB GZ Prem - I'll get it somewhere between now and the end of time, hopefully. That was because my wife has upped the count that I can have from two to three.
For the most part, it's not the money for me now, but like an earlier poster said, it's a value proposition. I could get a GZ Pro a lot faster, but the Prem has many more 'things' that I just WANT and think it makes it much more enjoyable. But I could/would not say the same for the difference between DP Pro/Prem.