Since no one has taken up this issue, I'll reply to my own question ... :D

I wrote: BTW, I believe touch switches to be in reasonable shape - we have left the machine in the same cycle for years and basically only use the start button. Translation: membrane switches have "low mileage".

Well, after further investigation and contemplation I have come to the conclusion that membrane switches do not deteriorate from use, they deteriorate from exposure to nearby heat and moisture.

Apparently there is a pending lawsuit against Maytag (owned by Whirlpool) to that effect citing:

"(the) poor design of the control panel ... allows moisture to enter the panel, causing many units to fail prematurely. Failures can be traced to the design of the control panel unit used on the dishwashers, which allows moisture to enter and collect in the unit's flexible membrane switch, or FMS, breaking down the coating on circuit traces within and allowing dendrites or metallic "whiskers" to form, causing a short circuit and requiring a $250 replacement unit."

Of course the big question was whether or not replacing the dishwasher control panel (including the touch switches) would solve my problem. This is an expensive part.

To confirm that the membrane switches were truly the culprit, I heated the switch panel with a hair dryer (set on 'high') at close range. After a few minutes of heating, the blinky lights STOPPED. I was then able to get the dishwasher to function to the point where it successfully ran a cycle.

I am now fairly confident that replacing the control panel would fix the problem. However, given the age of the machine (14+ years), I'm going to take my $250 - $300 and invest in a new dishwasher rather than repair this one.