the UK was a rare exception here, it is certainly not the norm
the dutch story is more complicated and closer, with napoleon being involved (again)
Spain, Portugal, France and the Netherlands lost their superpower status before the start of the 20th century
if you're in the year 2300, maybe the state Spain and Portugal ended up several hundred years after the loss of their superpower status is of interest
but today, the question we are interested is in "what happens at the point the US loses dominance over the world?"
will the US will handover the reigns to China in the way Britain did to the US?
the UK was a rare exception here, it is certainly not the norm