What is the point of having roads other than letting people moving into zones? When the zones are populated, you can destroy the roads, and it has no effect on the people. They seem to not care. No one was moving out, even after 50 years of no roads in a city with a population of 20,000.

I'm also wondering what's the point of having railroads when zones are not populated next to rails, but only next to the depots, but the depots cost $500 each.

They look nice.

Does it work similarly in Sim City 3000?

No.
Also, I've read that railroads are actually good for industry in 2000.