What an interesting way to look at things.
I've done 17 batches at approx 5 gallons each. If my math is correct that's 85 gallons. I only had to dump 5 gallons all year so that's a pretty good net yield of beer, with almost every drop going into my wife or my stomach. Sadly the pandemic has taken away a lot of opportunities for sharing and, frankly, I've not found there to be much "extra" beer beyond what I want to drink. Also a result of the pandemic.
Like Bubba Wade did, a person could really drill down on the cost/savings of their year of homebrewing. Personally, since I just started brewing this year, my equipment costs will destroy any savings over buying at the bottle shop. 2021 will be the year to really decide if this homebrewing thing is actually a money saver or just a new hobby.