Why is it a mistake to apply for wide patent protection?

Your IP strategy should basically be to protect what you are going to commercialize - therefore, your patents should be oriented toward what you have obviously developed and seek to commercialize. If you have the luxury, meaning funds and/or resources, you can then seek "defensive" patents, meaning, obtain patents which you would not necessarily commercialize but which would prevent others from making, using, or selling - or, in other words, commercializing. Remember - patents do not provide YOU, as the patent owner, the right to make, use, or sell what is patented - patents prevent OTHERS from making, using, and selling what you have patented. From a broad or macro viewpoint, things usually have a way of working out where you usually obtain patent coverage which you deserve, meaning, patents which are not really overly broad because other patents usually exist and your patents are either distinguishable from such prior patents or are improvements upon prior patents. Lastly, there may be an instance where you obtained a patent for product A, which happens to potentially infringe a patent owned by Company B, but Company B wants to produce what you have patented in connection with product A, so you can cross-license each other whereby you can both produce the product without exposing yourselves to infringement by the other party.