Lets see, we'll take 25GB and compare prices including other costs. If it cost $10, as the article suggests, to fit each produced disc/card and both are 25GB of data. It comes out to $12.25 per BR vs $32.50 (about a price difference of 1:3-ish rather than 1:10), again also as the article indicates. This comes with the added benefit of:
Games currently don't go over 32GB of space, but that isn't to say they never will. Especially if higher quality video/audio starts to be adopted. 4K maybe? Still the price of pressing discs is much, much cheaper. This seems to be a point you keep factoring out of the discussion. Price matters. Manufactures, especially when competing in the console market, want to keep them down and encourage sales to get people into their ecosystem. Someone has to pick up the costs if manufactures get extravagant with development. And you can get your bottom dollar it will be us, the consumer, who will do so.
In the link you provided, (provided these numbers are accurate) a BD DL (50 GB) was $0.09 per GB while SDHC (32GB) was $0.90 per GB! That is 10 times the cost per GB ! That is an insane increase. You do that over millions of units and it is a whole lotta mulah... For very little reward.
1. Ever device is already equipped with a method to read it.
2. The device that reads the media is cheaper (I can buy a multicard reader for $4.99, a Blu-Ray player is >= 10x that cost)
3. The media can be updated over time, meaning an error in your menu/subtitles can be fixed (instead of with a Blu-Ray disc you would have to repurchase the video to correct the issue).
4. Zero noise (in a cinematic/immersive environment this is priceless)
5. Faster loading times (for movies and games, allowing you to experience your purchase sooner)
And more that has all been mentioned in the article. Cost is the only thing holding media such as SD/Flash back. And there are many reasons to deal with that cost.