These cars must have migrated else where. Most likely blocking another lane of traffic else where.
While we don't yet have empirical data for this specific project set, your hypothesis is unlikely and inconsistent with past major street parking reductions.
In general, you get a modest decline in demand, most cars parked on main streets are not local residents, they are business owners and employees, and visitors to the area, some won't come to that area anymore, some will come by transit.
The remainder will continue to drive, but will park at the rear of their business in many cases and/or laneway parking, or paid off-street parking, or finally, on local side streets.
If you were parking on Bathurst between Harbord and Bloor, you can't just relocate to the next major N-S street over, that's ~1km away. Bloor is paid parking, and is not obstructing transit, perhaps you might find legal parking on Harbord, but it would it likely involve paying and/or greater distance or or both.
Apply that logic to virtually any paid space eliminated on Bathurst or Dufferin.
A 10-20% reduction in demand, the rest is shifted to side streets, or legal, off-street parking.