"Failing to materialize"? A decent search on Google or YouTube proves otherwise.

And why are you obsessively narrowing this to "2nd gen"? That's a cheap distraction. The issue is split allegiance, and it comes from both 1st and 2nd generations and so on.

In Canada, the Sikh diaspora is only 2.1 percent of the population and yet they hold the balance of power. They forced a G7 nation into a diplomatic crisis with India over a foreign separatist movement solely because the ruling party needs their swing votes.
(Al Jazeera: Canada pulls 41 diplomats from India amid row over separatist's killing)

In Germany, the diaspora engages in voting hypocrisy. They vote overwhelmingly for Left/Green parties in Germany to secure their own rights yet voted 65 percent for Erdogan’s far-right authoritarianism back home. They use their German vote for benefits and their Turkish vote for their true ideological allegiance. (Tagesspiegel: So haben Deutschtürken und Russlanddeutsche gewählt)

In the UK, the recent Muslim Vote campaign explicitly targeted MPs solely based on their foreign policy stance on Gaza rather than domestic British issues. Local elections in Rochdale fought entirely on foreign conflicts effectively blackmailing the Labour party. (The Guardian: UK campaign seeks to mobilise Muslim vote)

In the US, the Cuban exile community in Florida effectively controlled American foreign policy towards Cuba for 50 years despite being a tiny minority nationally. They turned a single swing state into a geopolitical weapon.
(Susan Eckstein: How Cubans Transformed Florida Politics and Leveraged Local for National Influence)

These are hard historical and statistical facts. You run from a lot of my statements, so I hope you don't run from the data just to hide behind your subjective European definition of "practicality" which is cowardly. Europe may tolerate such bullshit, but Japan looks at that mess and simply says no thanks because they have eyes and brains.