It's an interesting idea, but even if we accept the premise that overworked people spend so much more on convenience that companies get more back than it costs to pay them to work so much, it doesn't really make sense from a game-theoretic perspective. It's a prisoner's dilemma.
Every company is better off if they all ask staff to work 40 hours, so people have less free time and buy more conveniences. However, each individual company has the choice of paying their own staff to work those extra hours, in exchange for their own staff buying more of the company's own conveniences.
A quick glance at any real company will show that staff tend not to spend 10%, 20%, 30%+ of their paychecks on the products/services their employer sells. If they are buying more conveniences due to having less free time, they are buying from other companies - and this does not incentivise their own employer to pay for them to work those extra hours.
Also, many companies employ staff for 40 hours, but sell necessities rather than conveniences, and these companies aren't expecting to benefit at all from overworked staff. The only way this could be a real explanation is if it is combined with some reason for companies to individually make decisions for the benefit of all companies, rather than for their own benefit. Maybe it's a big conspiracy? I doubt it.
It sounds more like the author imagines "corporations" as one big, homogenous mass, rather than a diverse population, each with individual motivations that often don't align with the motivations of other corporations.