The entire thing is packet-switched, like the internet.
What you're saying about transfering lines is necessary because the vehicle itself only goes on one loop. You transfer green line to red, you need a different train.
The Skytran system handles all that.
As for the PRT and Republican thing, any good idea can become the basis for a con. The Simpsons and monorail is the classic cartoon example but we can look at the speculative railroad bubbles of the 19th century. Was rail the future? Yeah. Were the early investors going to lose their shirts to scumbag promoters? Yeah.