Cities have relatively fixed populations. The problem is not allowing everyone to drive their own car: that's stupid. The problem is how to persuade more people to catch the bus/train. Building roads doesn't make anyone's life any easier or better because it just persuades people to drive instead of catching public transport. Less roads actually helps because public transport gets better.

Your analogy is broken because building more servers doesn't "get more users". You have to service a fixed number of users in the most efficient manner possible. Providing a car lane for each of them is not efficient.