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 pinheads over the last ten years 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.
i actually want to know what innovation stern have done since the days of 90's dmd's? its been over a decade and we have not seen any new innovation in pinball, the change from a 70's machine to a 80's machine is noticeable, a change from a 80's to a 90's machine is noticeable but from 90's to 00's and now we are into the 10's and there isnt an once of difference really. and thats over 20 years and we are stil lat the same level of inovation.
its not just a matter of difference of display cow, but look at the difference in games and layouts from reel's to alfa scores to dmd's. when you compare how the display is along with the games them selves they all changed together in most parts. and no upgrade really from the late nineties till now on either game layouts and display. i fail to see how a later stern is any better than a dmd of the 90's, they are the same machines and you have to agree that is the case cow corner. only difference is one is new and one is old, it would be like holden selling the same model como for 20 years and not changing it, and the only reason you could say to buy that car is because the old one is worn out not because it is any different.
lucky stern arent a phone company lol, you would be still walking around with brick sized mobiles from 1990, lol
