It's cheaper to maintain extra fat sidewalks and stuff than 2 more lanes of asfalct also.
4 lane roads are the worst, you can get the same effect with a 2 lane with a turn.
It really depends on how many intersection you have, having a single lane that only branches to 2 in front of an intersection can be more efficient, then constantly 2 lanes.
The US style of many lanes, many intersections, is horrible from safety and a flow perspective.
Example: https://zuidas.nl/wp-content/uploads/2021/03/groenstrook-bee...
Look at the video in [0]: how much space would you need if every single cyclist was driving a large SUV? Look how smooth the traffic flows through the intersection, how many flyovers would you need to achieve this with cars?
Yes, cycle infrastructure does indeed take up a nonzero amount of space. But it easily pays for itself by reducing the need for far more space-consuming car infrastructure.
This is a logical leap of enormous magnitude.