Sometimes it is logical and fits and supports the story. Rarely. But mostly, it's intrusions. Consider how often in your life the ecosystem about you is manifest in all its intricacies. You're much more likely to notice animals and plants only if they are actually significant; otherwise plants are merely backdrop, and animals appear as bits of local color. Which is actually how they feature in most fantasy novels -- and exactly what the Tough Guide sneers at.
Economies are sometimes a weak factor. Bandits ought to exist only along well traveled roads, with plenty of plunder; pirates, on similar sea-routes. Your gentleman thief can only live in a society -- probably a city, or a country in which he can travel easily -- that has enough prey for him. Still more your thieves' guild.
On the other hand, how much will your characters know about the trade and industry involved? Noticeable industries -- noisy, noisome, what have you -- for that very reason tend to be performed where not easily viewed. And even when they are visible, when will a character notice them? Only when they directly intrude on his life. Street vendors he wants to buy breakfast from, captains he wants to book passage with, the innkeeper whose inn he wants to stay the night in, and the like. Some stories can take more than others, because it fits logically: when the troubled times are a direct problem for the character, when economics has become politically charged and politics ties into the plot of the novel. Outside this conditions, though, everything else, not the character's immediate economic concerns, is background noise.
And it is aesthetically unsound to promote background noise to a major concern in any story whatsoever.