I sold my older (turns 30 this year) bike last summer in large part because I wanted to ride more and wrench less. Many parts are no longer available and I had to find used parts on Ebay. The fuel petcock for this bike was unique and nearly impossible to find a working one without buying the whole bike. I had to drill out the rivets in mine and replace the gasket with one made out of an old bicycle inner tube.
Yes you can get old ICE bikes running, but you will frequently be substituting parts and sometimes fabricating parts or mounting brackets.
Electric bikes are relatively simple, at least to me, compared to ICE bikes. At the moment, there is not a wide selection of components readily available yet, but I suspect in 30 years I will be able to find a dash, battery, charger, or motor controller that that I can make work on my Empulse. I suspect I could get a 30 year old IBM PC working from parts available on Ebay. One of my electric kilns is over 50 years old and I can still find new switches and elements that fit. Batteries will still store and release electricity, though you may have to replace or reprogram the charger to accommodate a different chemistry.
Electric bikes today are very low volume and in the future, replacement parts will likely require some modifications to make work. Once their sales volume increases, I believe they will be about as hard to restore as vintage bikes are today.
Sorry to hear you sold a bike that's been with you for so long, but happy to hear its a lot less wrenching for you!
Curious to see where e-biking goes in the future to compare today's "vintage" bikes.
Happy riding!
