I think a lot of these questions posed have already been answered comprehensively by urban planners. Urban planners understand how to make well crafted urban sp

I think a lot of these questions posed have already been answered comprehensively by urban planners. Urban planners understand how to make well crafted urban spaces that work well and make people happy. The larger issue is that many of these known solutions aren't being implemented due to established NIMBY interests that create an intractable political situation that prevents anything but the status quo. For example I'd point to how NYC has been transformed for the better by the shift of road space usage from exclusive car use to being more inclusive of cyclists and pedestrians. This was incredibly difficult to implement due to extreme push back from just about everyone. Eventually once people realized it was working for the better opposition started to melt away. Even with this positive example to cite, for many cities basic safety improvements such as separated bike lanes remain incredibly hard to implement due to local and business opposition. Additionally there are funding issues. This isn't the same country by country, but in Canada at least municipalities don't have a lot of tools to raise revenue and are very poor. Metro Vancouver had a 10 year plan to dramatically expand rapid transit but it didn't have the money to implement it. The vaguely transit-hostile provincial government wasn't about to help out. The province forced Metro Vancouver into a referendum on a new 0.5 cent sales tax to raise revenue but it was defeated. Here we have an example where the region's planners completely understand that they need to expand rapid transit to the region to better move people around the region and increase housing affordability, but there aren't the funds available to execute on the idea due to political ideology.