I've posted this before, and sorry to repeat myself, I'm going to do so again.
It seems that lots of people blame our dying town centres on high business rates. They also moan when council taxes go up. They also moan when services get cut because they only see their taxes increasing while being blissfully unaware of what councils are legally obliged to spend money on and how they get revenue from different sources.
Most days I'll see someone complain about potholes on social media. The same people moan about rises in council tax. They want to fork out less for better services, or they want to fork out less because they don't use some services. They are often the same people who think they should get to the front of the queue in the NHS because they've paid into it for so long.
As for 20mph, I see no evidence of that affecting our town centres in terms of footfall. One of the biggest problems that affects footfall in our towns is rising cost of living and less disposable income.
You might notice that I've not mentioned any political parties here, mainly because I see that as almost irrelevant to this issue.