Product info on a lot of retail sites in my experience is restricted by legacy databases and info available from the retailer and their 3rd party IT. The website doesn't exist in isolation, as the article mentions, users want to see availability of an item ("only 3 left, order now and don't miss out"). There's your clue there. That data is linked to ordering and logistics data, often for a chain that operates hundreds of shops, including brick and mortar shops. Retailers want _all_ of the inventory available at all times, especially in season driven textile retail. Once the season ends you either sell it at knock down price or discard it.

Transfer of stock between brick and mortar locations and the central warehouse happens. Stock is ordered in 3-6 months in advance. Retailers ideally want zero of an item in inventory when new stock arrives.

The data discussed in the article is part of a much bigger system with integration left and right in a much wider spectrum than is being discussed in the article. Not that that shouldn't spur everyone involved into action; creating the solution that increases sales the most, just that it isn't as easy as this guy makes it out to be.