If you’re wondering why you no longer can update your quantity for product variants on your product page or where the product bulk editor field for Quantity disappeared to…
Why would Shopify do this? When you have a catalog of over 300 products and 15,000 Sku Variants, it was much easier to select the 5 or 6 products and bulk edit the variants. I contacted support and was basically told to rely on an import. There is WAY too much room for error with a bulk import if you are inexperienced. There is also a lot of time wasted as well if you have to export, update the spreadsheet, test that import, and then do the final import!
With the product variants, now you have to go into the variants separately whereas before you could change the quantities within the product page itself and hit save.

