I used to be a total petrol head and like you 'hrc monty' I too used to worry of it happening within my lifetime, but nowadays I am ready for the change and love inovation. It will be a whole different challenge for not only engineers but as riders, car drivers, etc.
If you have seen the Tesla sports car it has masses of torque and this will be ideal for trials where instant power is required with zero run up to catapult up rock steps and climbs. "Bring it on" I say.
I have managed to enjoy many aspects of motorsport provided by the internal combustion engines including sprints, rallying, karting, trials and enduro so I feel fulfilled and satisfied to wave goodbye. Having said that I would advise any youngsters to get as much use and experience from petrol/deisel engines before they are banned altogether.