That's a really good point, I hope at the very least it enables a "car -> public transport -> bikes" flow. So even if these people were taking the metro, all that extra metro space can accomodate car-owners who wish to switch.

It depends though. At least in London a lot of cycleways were made by removing bus lanes and replacing them with high quality segregated cycle lanes.

This has led to a big increase in %age terms of cyclists in London, but a fairly significant decline in bus passengers.

I think roughly 300m/yr cycle journeys were added, but bus has lost 500m pax/yr (mainly because of increased congestion making them less and less attractive). Note this isn't all down to bus lane removal, but it's a significant part of it.