I can understand congestion taxes, or limits to bringing vehicles into the central city for the day (to reduce the impact on parking needs, more than to alleviate congestion - a commuting trip is a vehicle on the highway, regardless of who owns it). There will be many people whose travel needs include destinations where communal cars can't or won't go.
Simple economics and lifestyle choices ought to manage this, once shared cars become available.
I do not think laws eliminating ownership are needed, as simple economics will simply make it more unaffordable to own a car in a few generations. Worldwide carbon laws, to things like making hailing daily becoming cheaper totalled than the monthly payments.
Also, if automated-taxi fares approach a TTC fare we may suddenly find a few hundred thousand additional people trying to use full sized vehicles instead of squeezing onto the bus/lrv/subway. A congestion surcharge will become essential, but again this will occur years and years after the problem is severe.
That is where relative pricing differences will solve this. It will be more expensive to take solo than as a group.
As hailing becomes popular and consists of say, a New York sized percentage of vehicles on the road (eg 25 percent of vehicles on road are hailable rides of all kinds, including those run by TTC and GO), the more optimized delay-free carpools becomes available (ie hailing an existing carpool already headed past you) ... The more attractive the carpool option becomes. Minibus mostly-fixed routes that dopoff you two blocks from destination, four-passenger all-the-way-to-front-door carpools, solo occupant taxis.
All the above would have more similar arrival times than today once the fleet is large enough that so many carpool options exist, that a route-matched low fare carpool minibus is easy to hail.
Imagine an app, like a supercharged Transit App, that presents you a list of arrival times and prices, and you just choose the cheapest ride (including public dial-a-bus clones) that keeps you on time.
Invariably, it will increasingly almost always be a pooled vehicle of some kind (including, of course, full size buses that are dynamically assigned to a brand new fixed route of incredible carpool demand).
Brand new bus routes created daily on demand! Ethereally appearing and disappearing. Basically a bus run as a superset of 100 identical-route carpools, and any available nearby unused bus is instantly dispatched when a computer recognizes hail surges on specific routes! People standing distributed over a whole block or two would be directed to walk to the dynamic "bus stop" a few meters away to reduce the number of stopping.
The route would literally be fixed anyway by default simply because of sheer number of people on an optimal bus-route-style itinerary created realtime on demand. So it would not be slower than a real pre-determined official bus route...
Obviously this would be in the situation of sheer number of near-identical carpools...it is simply dynamically merging and using the largest available vehicle that meets the time-arrival needs of everyone (including all pickups).
You doth day much ado about nothing, when you can brainstorm things like the above....
Obviously, congestion charges may still apply, to help coax more people into fewer hailed vehicles, translating into bigger price differential between small and large "carpools" (including "bus routes" as a bus running as a giant carpool)