Re: biological need
I think the author took too much of a short cut. The needs are still there, but there is no challenge in meeting them. We don't have to devote 3/4 of our day to hunting or harvesting our food and seeking shelter.
Or perhaps the author simply meant we have no "need" because these are all met.
In any case, it's an extension of the proverb that idle hands do the devil's work. Because we don't need to devote ourselves to seeing to our biological needs, the mind has time to get itself in trouble.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.