The patent times was established in a time were development times were considerably longer. Even if one is entirely in favor of the patent system as it is, the

The patent times was established in a time were development times were considerably longer. Even if one is entirely in favor of the patent system as it is, the expiry time should be shortened in order to match the original idea. How many (software) industrial year correspond to 20 years in the nineteenth century? Say, 5? This would drastically improve the patent problem considerably, without having to change the substance of patents legislation.