I think that is a different tangent. Regarding argument of scalpers, They buy it to sell at a profit. Inventory with them/In transit shouldn't be more than 15 days. Simply put, premium they could earn decays on holding. They have no incentive to hold and all the more incentive to sell.
Also they do not properly disclose their data source. Could be a bit off. You might want to take these numbers with a pinch of salt. Original video link https://www.youtube.com/watch?v=mKgtpVTh-B0&ab_channel=GamesIndustry.biz.
Longer term digital is ~70%. Possibly due to convenience in buying cheaper games during sales. Right now not a lot of ps5 games exist and they are definitely not discounted except maybe 1 or 2 recent release. What you are saying will increase the disc vs digital divide and is correct but I still feel a lot of this is coming from forced bundling. Have no way to quantify it though.
Amazon has a 5% off. A 10% sale mostly comes once or twice a month which is 14.5%. I can also DM a guy's number. Have bought vouchers a few times at 15% from him but I prefer Amazon/Tatacliq If I can get the same 15%