For example:
* https://tfl.gov.uk/corporate/publications-and-reports/econom...
* https://cyclingsolutions.info/cost-benefit-of-cycling-infras...
* https://cyclingindustry.news/724m-in-economic-benefit-on-80m...
In my anecdotal experience from the UK, high streets have been destroyed because they have failed to keep up with what people want.
Decades back, we started copying the US and building lots of out of town shopping centres surrounded by acres of car parking. Town centres started to compete by making it easier to drive in urban areas - but in doing so, they made the environment much less pleasant (loud, dirty, unsafe etc.)
Over time, retail became homogenised to the degree that every high street and shopping centre had exactly the same set of shops. This worked until internet shopping arrived. Why go outside to shop when it doesn't offer anything that you can't get on the internet - cheaper, and with a larger selection?
Now the only thriving high streets are those that offer something more than the internet can. Unique independent shops; space for people to meet friends and relax; street cafes; art/culture and so on. Removing cars in favour of walking and cycling is one of simplest and most powerful tools available to achieve this.
