I'm not sure I agree with your assumption that correcting business rates won't have a significant impact. As I said before, why should personal home delivery be the cheapest option?
Why do you think that "the cheapest option" is what is required?
IMHO, it is a balance between price, convenience and availability.
An example (which does not, strictly speaking, involve the High Street). Recently, I needed to replace a Kitchen Tap. I knew what make/model I required, I shopped around, online, found the cheapest option (Screwfix). I have the option of two branches, both within 3-4 miles, I chose the one with best parking option, and typically least traffic en-route, did "click and collect" to buy said tap. Whilst fitting the tap, I found I needed either replacement isolating valves, or, two male-female adaptors. Quick check online, two new isolating valves were cheaper than two adaptors, Screwfix was slightly cheaper, but, not available until next day, Toolstation had stock, marginally dearer (about 50p) but, nearest branch has poor parking options and the route there is traffic congested. On balance (ie getting the job done), I opted for Toolstation. As I said, it is not all about price, it is much more nuanced than that.