The countries with the most dense populations in the world are 1. Macau (48,000 per square mile), 2. Monaco (43,000 psqm, 3. Hong Kong (16,444 psqm) 4. Gibraltar, 5. Bahrain, 6. Malta, 7. Bermuda ........ 14. Mauritius, ..... 19. Netherlands, 20. Belgium, 21 Japan............
Britain is 53rd place (660 per square mile) in population density. Just below us is Germany at 56, then Italy at 62 and Switzerland at 68.
There doesn't appear to be much of a correlation between population density and wealth, although some countries, such as Hong Kong and Singapore are very densely populated and very wealthy.
Some people seem to overlook the widely held view that our and the US's actions in the Middle East have contributed significantly to the political, economic, social and military turmoil that exists in the countries from which these people are fleeing. How such countries are to be made "safe to live in" goodness only knows - and even if it is possible it will take a very long time, whereas these people need help now.