Essentially all tank are is a heavily armored & very mobile weapons platforms on a track that also can inspire psychological responses in regards to the battle itself. That said:
Many figure the Main Battle Tank as we know it is about dead. Unless a new superpower with technological, economical and manufacturing capacities beyond our wildest dreams, immerges overnight to provide the ultimate in military surprise, we are going to maintain the almost ten year technological advantage over everyone else. This can easily be shown as a horizontal line on the technological S curve. Without competition to our MBT; its own advanced ability has flatlined its further progress line.
One thing to remember is that the horse cav took forever to finally be reduced to a non essential military asset. This was mainly due to its outdated but politically strong supporters. The loss of ground from horse to mech was primarily due to the machine gun. Would it be too much to imagine a new tactic being able to stop the tank all the time? Masterplays are not unheard of, rare as they are.
I do see the battle suit as something to either replace the tank or work in conjunction with the tank. Most problems with the battle suit that SF does not deal with well is the logistical support of the suit and that may well be the role that the MBT could most significantly fill. Its heavier weapon or weapons are a welcome addition to the field; but the main weapon would have to be significantly better than the package that the battle suit could offer.
In that futuristic set piece battle, the tank works as long as we deal with conventional armies. Unconventional armies such as of cells and loose, undefined command and control structures will maintain an advantage over the set piece battle as they are not seeking a decisive tactical battle but a series of strategical and significant losses (though economically bias to a win). Totally different doctrine. Too bad it is off the subject except periphierally.
To me, the MBT has to be developed to handle a broader expense of missions as well as the missions that it has already. Alot more should be expected from the new MBT if they are to be developed further.
I did look up the Swed S tank, by the way; did like that chassis idea; it brought to mind that really complex skateboard truck with all the springs from the sixties, if anyone else remembers the issues with that

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The Mainer
The Mainer...