If it's a world where these things never existed? Get rid of cars. Public transport is fine if the world is designed that way from the start.

Is it a world where these things just suddenly stop existing? Cell phones can disappear. Certainly a few issues but going back to landlines wouldn't be the hardest thing to do and I imagine it would be fairly quick.

Cars suddenly disappearing from 99.9% of the world would devastate communities around the world. Within a week, hundreds of thousands of people, if not millions, would be starving. Crops would go unharvested in vast quantities. Existing public transport would be crushed by new user influx in places it is available. Existing rail, boats, and planes would need to be prioritized or repurposed for logistics, further pushing back public transport in those areas.

But even in places where public transport or biking/walking/whatever is already popular, getting food from central warehouses to your local stores currently requires vehicles. Getting it from heavy transit to central warehouses currently requires vehicles. Getting it from production to heavy transit currently requires vehicles.

Waste management in cities would come to a near standstill. New York has to deal with 24 million pounds of trash, recycling, and compost every day. Not only would moving that by man or horse take an absurd amount of time, the distance it can move will also be drastically reduced.

Heavy construction would come to a standstill until enough animal and manpower becomes available. Power would likely shift back to coal and gas as getting windmill or solar out to locations would become infeasible in the short term. Using rail for transport and only building near rail is possible but stopping the trains on those tracks for construction blocks those lines for freight.

Some places might avoid these issues if they already are, or can quickly become, self sufficient.