I actually don't think Tiger parenting is more special than, say, just investing in your kids more broadly. You don't have to be an authoritarian and still get excellent results by caring about the success of your children in society and also having the resources and means in which to perform that investment.
More likely is that filters for immigration are very high, which means the average immigrant is more educated, wealthier, dedicated, etc. than the average born-citizen.
Tiger parenting is one way of investing in your kid. I agree, there are multiple ways to invest in your kid.
>More likely is that filters for immigration are very high
Don't agree with this, there are lots of ways to immigrate and I don't think most of them have a sort of wealth/education filter. For example refugees.
Refugees are pretty much the only category that doesn't have some kind of wealth filter, if only because immigration paperwork costs a fair bit of money (esp. when you look at it from the perspective of someone in a country where cost of living is much lower than in US).
And the majority of immigrants in US aren't refugees.
Self selection among immigrants is easily the largest factor behind their higher rates of success. Even as a refuge, there were tons of applicants, there is almost surely a reason you are the one who made it. It's in no way an easy process.
While parent's comment was certainly to some degree tongue-in-cheek, they are likely agreeing with you. Investment in your parents AND likely a higher than average weight on "a good life" being grounded in employment, education, and certain values are contributing factors to the end results
Parents matter.
https://en.wikipedia.org/wiki/Tiger_parenting