I decided to look into how many retail booster boxes would have to exist for it to match the volume of Kickstarter booster. Currently on GTS Distribution you're allowed to purchase 1 Kickstarter Case for every 2 Retail Case if I'm not mistaken. I will assume that retailers are all using this opportunity to purchase a Kickstarter case as it would be significantly cheaper through distribution then it would be to back the kick starter.
There a currently 6 completed Tier 7
1 completed tier is 54 booster boxes x 100 backers = 5400 Boxes
6 completed tier = 32,400 boxes
Incomplete Tier 7 (Goro - 35) + (Male V - 19) + (Jackie -79) = 133 Backers = 7182 boosters
39,582 boosters
Tier 6 - 730 backers * 18 booster = 13140
52,722 boosters
Tier 5 - 2967 backers * 6 booster = 17802
70,524 booster
Tier 4 - 9400 backers * 3 booster = 28200
98,724
Tier 3 - 22,310 backers * 2 booster = 44,620
143,344
Tier 2 - 3,398 backers * 1 booster = 3,398
146,742
146,742 booster / 6 = 24,457 cases
Now if every retailer also purchases a Kickstarter case along with every 2 retail cases they purchase then it the total amount of retail cases would be 48,914 as well as 48,914 kickstarter cases or 293,484 booster boxes each. 586,968 booster boxes in circulation. 4 Times the amount available Riftbound or one piece boosters on release.