> makes your own economy better off

just because the overall economy is better off (often measured in GDP) doesn't mean it is better off for all existing residents (e.g. GDP/capita).. even from a pure free-market perspective, distribution of wealth is not so market driven especially in the short term and when massive distortions deliberately exist in the marketplace (regulation, patents, near-monopolies, barriers, etc.)

Do you have a source. Do these economists say there should be no limits on immigration?

It's a balance, if you don't have enough immigration you want more, if you have too much you want less. Which side of the curve the US is on is debatable.

The rate-limiting analogy can work: thing is the boat is leaking, so you think that if you let someone in it will leak quicker. And it will. But when you let someone in then you can bail it out and they can row (or vice-versa). You're still sinking but actually slower and now you can move too. Let someone else on and you can stop the sinking.

Testing the limits of the analogy, but there you are.

Working well, generally:

http://fortune.com/2015/09/08/germany-migrant-crisis/

>The 6.6 million people living in Germany with foreign passports paid $4,127 more in taxes and social security on average than they took in social benefits in 2012--generating a surplus of 22 billion euros that year, according to one report

More recently:

https://qz.com/901076/what-effect-did-the-record-influx-of-r...

I have no idea how that's working out for Germany. But I was under the impression that Europe gives away social benefits to the refugees (at least at the initial stage). While the author of the parent comment (I expect) is self sufficient from day 1 (otherwise, he / she wouldn't be allowed in, right?). It's not like the government of the US is spending people's taxes on him / her. He / she paid for the interview with the embassy, paid for the visa, then was paying taxes and spending money locally buying food / clothes / etc. (thus creating / supporting new jobs).