I work in web dev, copy writing, ecommerce, and marketing. I work about 5 hours a day, sometimes even less. My work always gets done and is impeccable (I would feel bad otherwise). Of course, some days I work way more, as there is a project giving some issues that need to be addressed. Not scared of a 20-hour+ marathon--sometimes it has to happen, especially when working in tech when issues can happen at any time.

I've been a founder and CEO. I've represented startups when I was an I.P. attorney, and later consulted for startups on the business side.

Have you actually worked with developing websites, apps, and e-commerce platforms in regards to the article mentioned? If not, the article you copy-pasted (or summarized) wouldn't be much value to you, as you wouldn't understand completely. It is a completely different industry on its own and would require a different outlook.

If you have a hard time cutting work out after 10-hour days, either your processes are highly inefficient, your employees aren't the 'right' ones, you're under staffed, or a combo of any of the mentioned.