Big Things include:
Job Kids Spouse Social Life Major Hobby (e.g. build a boat in the garage, become a chess master, video game addiction) Startup
This seems to be saying that an employed married person who spends time with his kids and friends is an impossibility. Since that's obvious nonsense, what is it saying?
Well, what it’s actually saying is that the hypothetical employed married person who spends time with his kids and friends is shitty at two of those things. (Perhaps more, or even all, but at least two - because, you know, that’s the rule of life.) What an inspiring and actionable message.
I grant that as a married person with a job and kids, I’m not great at pursuing hobbies or spending a ton of time with my friends, but I love the author’s implication that either my job, my spouse or my kids was just a bridge too far and I’m just out of luck when it comes to one of those.
It makes about as much sense as saying that having a successful career requires 20 hours per day and is therefore impossible unless you sleep 4 hours a night. You can say that, but it's just untrue on the face of it, unless you redefine "successful" to mean "something you spend at least 20 hours per day on."
But the overall message is fine, if obvious. You have to prioritize, you can't do everything.