I don't believe that's historic; the landmine convention was drafted in 1997, and the cluster bomb one in 2008. The European nations that dominated these movements (USA signed neither) were in peacetime, and had known nothing other than peace for a very long time.
The treaties they're withdrawing from today aren't the post-WW1 Geneva conventions; they are modern treaties that were in actuality products of eras of peace.
Europe has been dealing with unexploded ordinance from the fallout of European wars for over a century.
Of the countries you listed, its the US that has not actually known war. A few of its cities being reduced to rubble and a few thousand of its children losing limbs to land mines might convince some more of its people that war isn't quite the swell adventure they think it is.
> I don't believe that's historic; the landmine convention was drafted in 1997, and the cluster bomb one in 2008
Not historic in the sense of 'old', but still motivated by real horrors that Europe witnessed. The Bosnian War occurred only a couple of years prior to 1997 and left the region with over a thousand square kilometres of land contaminated by live landmines, which are still being cleared today. I don't know about cluster bombs specifically, but I would imagine that the (widely televised) Second Gulf War and the conflict between Israel and Lebanon had something to do with changing European perception of the weapons.
Certainly, the treaties are always drawn up in peacetime - it would be impractical to do so during an active conflict. However I believe that all of them have been prompted by some violent, horrific conflict in the years immediately beforehand.