Bikes have already taken market shares from cars in large European cities such as Amsterdam [0] or Paris [1]. They may be a superior technology for most urban commutes: faster, requiring less space on roads and for parking, and more enjoyable [2].
Buses are subsidized. In cities with subways, they are used primarily to accommodate people with limited mobility or to cover rare routes. Between cities, they remain the cheapest option. Therefore, I'm not sure that cost is an important factor.