Different companies have different levels of risk tolerance. I've worked at companies whose tolerance for risk is so low that they don't even touch anything that might be covered by a competitor's patent--even if that patent is clearly so broad that it wouldn't stand up in court, or is invalidated by the existence of prior art. The fact that it was written on a patent meant that we needed to circumvent their claims entirely. So if you were a competitor, it was definitely in your best interest to patent as much as you can... Even if you had no plans to enforce them.