Another problem with this strategy is often balance - in the end game you may be getting tons of cards, but if they're not combining well with each other you'll be left trading with the bank very inefficiently.
This strategy aims to collect more resources than anyone else, and use the sheer weight of production volume to overwhelm your competitors. It makes no special attempt at either Longest Road or Largest Army until a powerful engine based on 6-8 points of cities and settlements is in place, at which point resources are rolling in at a furious pace and you coast to victory. However, it is likely the more focused strategies will shut you out of both of the bonus cards unless you are really crushing them with production, and it will be impossible for your opponents to ignore your wealth and you'll get hit with the robber a lot. Another problem with this strategy is often balance - in the end game you may be getting tons of cards, but if they're not combining well with each other you'll be left trading with the bank very inefficiently. It's hard to win as Producer without getting a least one good port.