How in the world is that at all like Shatner's famous appearance on SNL? Is there a
less famous Shatner appearance where he dispensed realistic acting advice to an aspiring thespian, with a checklist of things they needed to do to hone their craft? All Tomino said is that one would likely be happier being an office drone, because it's a tough industry to break into and succeed in.
Personally, I've always thought that was a silly thing to harp on (you see it in American media as well, particularly comics), since it's so very obvious, and it applies to any industry, and any field. Being a good lawyer, for example, requires a lot of hard work and dedication, too. Or a good doctor, scientist, or businessperson.
That said, there's this:
you will need to push yourself to do at least three drawings a day
If this means what I think it means, this is why I dislike manga. "Drawing" is a really vague term, but if it does mean "page," three pages a day is tremendous output, and there's no way the work can be top quality at that pace.
Of course, maybe I sound like General Motors in the 1960s talking about how no one would ever want to buy Japanese cars.