Lifespan chain and gear wheels on e-bike
It’s impossible to give an answer because chain and sprocket wear is dependent on load as well as distance. Stronger or heavier riders apply more force. Riding lots of hills will do the same.

The best approach is to get a chain wear gauge and record how long a chain lasts for you and your riding. 

Conventional wisdom is 2 or 3 chains per cassette. Inspect the cassette when you replace the chain.