In the really long run
everything humans have ever made except for the pyramids is unstable. It would be really strange if the current living generation is somehow the exception. Houses are built for a couple of decades, they sometimes stand for a hundred years or more but that's not the rule and should not be taken as guidance for the future. Companies can move if there is enough time.
What will happen is that at some point - still quite a bit into the future - humanity as a whole will have to adjust to a new coastline and as long as it is economically viable they'll try to milk the structures already built. But in the end, on that timescale it is a non-event.
A bigger question will be how we will house and feed a 10 billion plus number of human beings on a reduced landmass with all the 'good bits' already taken. There will be wars and famine in that future and I don't think we will be able to avoid that forever. Again, history is full of upheaval, we certainly won't have seen the last of it.
But to suggest NL will disappear in the next couple of years/decades is not in line with my expectations based on what I know about this stuff. (More than most, less than what I would like to know but there is only so much time.)
As for the rivers, pumping out the water forcibly would allow the surge barriers to remain in place but would severely disrupt the economy (harbors inaccessible) and would require pumping capacity that we currently do not have (those rivers carry an enormous amount of water).