Activision just had a record-setting year of high revenue (presumably they are not feeling the impact of peaking attention), in part because the quality of their products is still high-ish. They laid people off because they could, not because of any downturn in business.
EA's quarterly results are down, because their product quality has suffered and their pricing has risen, players are somewhat disengaging. Those problems are with EA and internal to EA, not problems with the industry.
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The article is right to claim that too much focus is on "Fortnite", but they miss their own point. These companies are not suffering from "peak attention", so much as they have stumbled into various mismanagement and/or bled out a chunk of their talent and ability to create. These companies problems are impacting the products they ship.
If you build a well designed, well crafted product, players will still happily arrive and spend lots of money (as EA's own Apex Legends is showing today, and as Fortnite, Spider-Man, RDR2, Warframe, Path of Exile, Magic Arena, and many others routinely demonstrate.)