I think you'll find that this imagined generality does not go as far as you would like. Mines tend to be on hard ground while farms tend to be on dirt, make a tractor too heavy and it'll get bogged. When the tractor is an hours drive away from the nearest power outlet it just does not seem realistic. Diesel-electric can make a lot of sense, the fuel is the same and it does the same thing but more efficiently and with lower maintenance costs. I don't hate the idea of fully electric, if anyone can make the math work then great, but for the use case I mentioned I highly doubt it.