If you aren’t going to give us walkable cities or really efficient public transit, then we need cars and therefore need the parking. There is no way in this or any world that I am hauling $300 worth of groceries to a bus stop, just to sit there and wait half an hour (at -20C) for a dilapidated bus that may or may not even run on time and has the risk of someone stealing some of those overpriced groceries on the 30 minute ride it would take to get home.
I live in Saskatchewan and it will very frequently get to -30 or below. I cannot ride a bike in that safely without risk of frost bite, so cycling is out of the question (at least in the winter). I drive as small of a car as I could buy, but even small cars are dwindling now in favor of the giant SUV’s and pickup trucks that seem to think they own both the road and the parking lots. The public transit in my city is so inefficient that it would take me an hour worth of riding the bus, and a transfer, just to get downtown. I can drive that in 10 minutes. Getting to the other side of the city? 90 minutes to 2 hours and multiple transfers. Or 15 to 20 minutes by car.
Our public transit and walk-ability needs to be remedied long before you start building over parking lots. Businesses with no parking will suffer a lack of business if there is no parking and no change to the current systems.