Earlier quoted context omitted.
Bike lanes and bikes aren't alternatives to most of what motorized transport is providing.
Most car trips are very short, and commuting to a CBD is easily served by transit.
Each of those likely has possible alternatives to motorized transport, but they're all different alternatives. Meanwhile, today, they all share the same road network with regular civilian commute, sharing costs and mutually improving efficiency.
Put differently: instead of imagining all passenger cars replaced by bikes, imagine all roads replaced by bike lanes, then extrapolate from that.