Spain and Portugal had enormous, early, rich, colonial empires. Portugal in particular had a vast number of widespread colonies across the continents. Why were these kingdoms unable to parlay that colonial success into being global powers through the 19th and 20th centuries? I'm comparing to France and Britain, specifically.
Hi! You can find some excellent answers on this topic in this section of the faq, under 'The Decline of the Spanish Empire'.
Edit: As the faq's answers focus mostly on Spain, here's another great answer by u/Itsalrightwithme looking more at the Portuguese side.