I'm no expert, but in my mind, it stand to reason that the ECU is simply
reactive.  That is, it merely reacts to the inputs of the various sensors
and signals that are fed to it.  If it did "learn", the ton of folks that
have suffered from the dreaded "power loss after running for some time"
syndrome would not be able to continue on after the key is turned off and
the bus restarted.  Doing this resets the ECU, clearing the signals and
allowing the engine to run okay again for a period of time.  This
explanation is overly simplified, but is probably applicable...

Alan Bosch
& Phred ('88 Wolfsburg)
Rochester, NY