Maybe, but rarity is no guarantee of value and ‘on the rise’ and ‘£1900’ are quite different things.
Also it’s debatable as these games get older and the ‘I remember that from back in the day’ nostalgia gets less and less as the people who actually can remember them also get older, the fact that by any objective measure newer games are ‘better’ means that people who are new into pinball will much prefer DMD (and LCD now) digital sound and all the modern bells and whistles?
I have all the 1981 Bally games and I love them and have no intention of selling. They have a certain value and I would expect them to keep that for the time being, but eventually even those top rated games will get to the stage where the market for them gets so limited that their value will fall - so I think the value of ‘lesser’ older games definitely will.
IMHO anyway - time will tell if that’s anything like what actually happens! As I say literally no one wanted my EFTLW back in 2004 (ish) and that certainly wouldn’t be the case now, so markets change over time.