There's probably some spillover / upwards pressure from the successful US companies. But I think the main driver is that in Europe, software is mostly considere

There's probably some spillover / upwards pressure from the successful US companies. But I think the main driver is that in Europe, software is mostly considered a cost centre instead of a revenue centre. In Europe there are not that many successful tech giants, where programmers are seen as essential for bringing in the money. Rather, most programmers work in other industries supporting the main business.