One thing that makes our life difficult is that innovations tend to make things better – but not in every respect. Cost-saving improvements might be less robust and “cool” designs might be less prestigious, not to speak of the advantages and drawbacks of atomic energy or genetic engineering.
This ambivalent nature of innovations might be one of the reasons why the requirement that the invention is a “technical progress” has been banned from the list of requirements to be fulfilled by patentable inventions in Germany as of 1978.
Ever since, courts and offices struggle with the assessment of inventiveness for alleged inventions making things – at least in important aspects - worse than before. While the case law of the Technical Boards of Appeal still provides a special treatment for so-called “disadvantageous modifications” (see e.g. T119/89) in that they are basically non-inventive right away as long as the disadvantages are foreseeable and not outbalanced by surprising advantages, the BGH in Germany has banned any such judgmental considerations from the assessment of inventive step.
Rather, the “incentive” (Anregung) for the skilled person to modify the prior art has been implemented in the last years as a very strict requirement for the assessment of obviousness (see e.g. here and here).
In the decision “Kniehebelklemmvorrichtung”, the BGH applies this approach to a modification which ultimately turned out to have major drawbacks, the drawbacks being – according to the patentee - an incentive for the skilled person to return to the prior art or to make further modifications rather than adhering to the solution according to the patent.
The patentee’s argument that adhering to the disadvantageous solution of the patent would therefore be non-obvious was rejected. The BGH emphasizes that the decisive question is whether or not there was an incentive or pointer to make the modification.
To put it differently: As long as there is a pointer at the beginning of the street, it is obvious to follow it – even if it ultimately turns out to be a dead-end street.