[vidarh]

I think you're right that codifying what had previously existed as a de facto but no de jure right certainly was a direct response to increasing pressure from landowners to limit access.

Norway was in a similar situation in that until the 1950's the right was implicit - the one major area of law which was not codified because it was seen as so self-evident that it wasn't considered necessary (Sweden, in contrast, has it embedded in its constitution) - until pressure from land owners who increasingly started blocking off land in ways which violated of centuries of tradition made it clear it needed to be codified so it could be defended in court.

It's seen as integral enough to Norwegian culture that it's taught in primary school.