Retail parking is all about capacity, which directly relates to footfall. You can even work out average spend per car and per car park.
All of these views, including the British Parking assoc, are commenting and making suggestions on physical asset design, not parking operations design. This means that if you have 100 spaces in a mall, and you overfill them, no one will enjoy the experience but more importantly, you don't increase footfall, and therefore revenues in the mall. This is the norm for malls. By comparison if you have 50 spaces on-street (normally much less capacity) then the local shops are suffering through a lack of footfall.
An answer is to increase the turnover to achieve a desired occupancy rate over a period of the day to make the car parks as productive a possible, for as long as possible. This means the price might need to change a couple of times a day to encourage shopping in the High St at shoulder times, by price or time restriction (just means revenue comes through Enforcement not Operations).
A key understanding is that if you have 100 spaces and there are 150 cars seeking a spot, you still only have 100 shoppers, not 150....so why overfill them? Conversely, if you have if you only have 50 cars, the parking operation is equally as badly run.
The parking operation needs to be designed to allow for as many shopping parking opportunities as possible without having restrictions set too short or too long or prices too high or low. This might take some trial and error.
Once the best mix of price and/or restriction is found, to achieve 85% occupancy, then you need to work on increasing capacity, which is an asset issue, not a parking issue.
When everyone understands the science behind it, the issue is depoliticised as the emotion is removed, and it becomes an economics issue … where it should be.