Its still the same technology Cavey. The technology at the time was very common place... we werent in the dark ages. Problem is that the games you mention are still the same as the games churned out now. DMD was new at the time and was an innovation... its no longer an innovation, it is in fact a poor way to display graphics in todays market.
As for the game itself.. coils, micro switches etc, this has hardly changed in 100 years.. the micro replaced the leaf switch, optos negated the need for a protruding switch etc.
Hardly anything has changed since IJ and TZ
Plus you can then consider the ColorDMD (LCD) for titles such as MM, AFM and TAF and those 15-20 year old games have in effect "leapfrogged" the current Sterns. 
That doesn't make them better games, what is the big deal with displays anyway? I hardly ever look at a display while playing.
Leapfrogged in terms of technology. Stern in terms of technology have always been the followers, not the leaders.
The problem is that until JJP came on the scene, Stern was the only player and a lot of pinheads over the last ten years have developed this "apologist" mentality of, "well at least they are still making pinballs".
Stern were literally handed a unique (a virtual monopoly) market position and they failed to take the initiative (instead choosing to become complacent).
Gameplay is another matter altogether and is purely subjective at best.
