While under threat, other parts of the world are much less prepared than my home country, which has a long history of just engineering its way around the issues. We already have parts of the country meters below see level that are perfectly fine. One or two meters extra poses a few technical challenges but nothing that can't be handled. Important to note is that you have to separate averages and extremes. This is the north sea we're talking about. Water levels vary by several meters between low tide and high tide. Averages are meaningless and not a problem. It's the extremes getting more extreme that need planning for. Upgrading dikes and other defenses for higher water levels is costly but doable.
The automated barrier closure was triggered by the combination of a winter storm and high tide pushing in a lot of extra water up the river. Add to that saturated rivers draining essentially most of Europe's rainfall and you get a picture of what is routinely dealt with there. The rivers are actually a bigger issue than the sea. Forested areas that used to absorb a lot of water are vastly reduced in size. More extreme rainfall now flows straight into the Rhine and Meusse rivers, which both exit where this barrier is. The solution for this is not more dikes but flood zones.
Other parts of the world are much less ready for higher water levels. Florida for example is particularly poorly prepared for even modest water level rises and has much less extreme tides; so the averages matter more. There just isn't a whole lot in terms of sea defenses and other infrastructure. Any storm is likely to push a lot of water in. Combined with even modest sea level rises that means there just is a lot of property at risk.