Why wouldn't we build a vehicle that can drive on streets, on rails, can fly, swim and dig through the earth? It would be a marvellous construction. And awful e

Why wouldn't we build a vehicle that can drive on streets, on rails, can fly, swim and dig through the earth? It would be a marvellous construction. And awful engineering. I'm not blaming the person who builds the machine in the end, but the person that sets up the specification – they are doing a bad job.