There’s good reason to be cautious. These don’t always work well, and security can become an issue. Changing the built environment to support safe and active public spaces is challenging.
It would be great to know what factors make a pedestrian mall in a downtown core work well over the long haul and which don’t.
In the 1970s, several Canadian cities emulated European ones and created pedestrian spaces in their cores. Vancouver had a good length of Granville ‘theatre row’ closed for decades and Ottawa had Rideau closed to all but public transit. A great deal of infrastructure investment was made to make them appealing pedestrian spaces. Ottawa still has Sparks street completely vehicle free in the Parliamentary precinct.
Both Granville and Rideau were eventually reopened to traffic after they became crime focal points. Both were places women felt safe to walk on in the evening in the late 70s and early 80s, but by the 90s many pedestrians avoided them during the day and businesses left, replaced by boarded up storefronts.
All to say, not such a simple public good question as some are presenting here.