Why do I need a maglev to go 70? A bus can go 70. Any old steel-wheeled train can hit 200.
Why don't you look at a train schedule in the US and tell me how many trains go 200 mph. Hint: zero! Most trains average less than 50 mph.
As for a bus, you aren't going to drive it at 70 through the streets of LA or Manhattan. In fact, it's probably going to be tough getting it to 60 in this traffic:
http://www.mercurynews.com/wp-content/uploads/2016/10/sjm-co...
A maglev carries 200-300 people? Your average bus holds 50?