How long do you wear or lasts one Dexcom G5 sensor?

This makes perfect sense and also will explain how your Dexcom mg/dL
Average glucose (CGM) might be very different to your A1C since your A1C is measured on the same principal. The lower the peaks and valleys of your curve and the lower mg/dL
Standard deviation (CGM), the lower the A1C will be and possibly the longer the lifetime of the sensor.
If you really want to test it, you might need to find a non-diabetic test subject which should really have no deviation and compare the lifetime of the sensor to a diabetic since most of us have a certain deviation.

A good, but somewhat expensive way to do it, I would think we would need at least 3 sensor worth of data. Perhaps we could cobble something together.

I bet you that Dexcom has the exact data. Just one more reason to strive for the perfect results as the money motivator and understanding what the perfect results really are. Not your average glucose but the smallest deviation you can accomplish.
edit: slight brainfart here. The average glucose is as important as the deviation since 4-6% of glucose attachment to Hemoglobilin is considered normal and if your average goes up that percentage goes up and your deviation increases. That means your A1C gets higher and the sensor lifetime decreases.