Most of the new buildings in Mississauga are built right up to the sidewalk with street-level retail on the ground floors. They look like
this and
this and
this. I don't really see much difference compared to what built in Toronto. The car-oriented-ness of Mississauga is always exaggerated.
Ultimately you are not going to build many high-rises in a place that is too auto-oriented. It would be too expensive to provide for the all the parking and there is little reason for the home buyer to sacrifice space for proximity if they just going to drive anyways. You want more development in a smaller space, higher-density, then you need to get rid of the parking. And to get rid of parking, you need to get people out of their cars. Mississauga has good enough transit for high-rise apartments, but not good enough for high-rise office buildings. The high-rise construction is entirely residential.
Other cities are not building skyscrapers? They need to start investing in transit. Transit ridership is in decline all over the USA. That promotes lower density, not higher.