Interesting then that the US based its legal system on common law, inherited from a country based on a fairly strong monarchy, moreso when many left Europe in dissatisfaction with the conditions there.
Laws can be well thought out and well written at the time, yet will fail as the world evolves and can also be incorrectly applied. There is also the law of unintended consequences. Many countries have specialised courts or specialised judges to take care of IPR-related cases, even so an appeal will often show that the law was incorrectly applied. Also the same laws can be applied by the supreme courts in different countries and come to opposite conclusions.
Most of the European countries have acceded to the European Patent Convention (EPC). The European Patent Office (EPO), operating under EPC, runs seminars for Europe's top judges. Even so you still get totally different conclusions. Now the European Union is considering a centralised patent court. Unless something changes dramatically it will only mean you get to throw the dice once in Europe rather than once for each EU member state.