[strken]

The idea that immigrants are a good idea because they do labour your existing population won't do is quite socially destructive and the cause of technological stagnation. It separates people into a de facto caste system where unpleasant jobs are also underpaid, prevents automation from becoming cost effective, and can block a country from reaping the benefits of skilled migration.

[btbuildem]

I didn't mean to assign a value judgement to this -- maybe I can phrase it better. It's not that the "local" people don't want to do certain jobs, it's that the capital owners are not willing to pay fair wages for labour, and then only people who are desperate enough (poor immigrants) end up doing do these jobs.

I'd love to hear some examples where this has caused technological stagnation and blocked skilled migration -- US and Canada provide solid counter-examples to these claims. Both countries take in immigrants at both ends of the economic spectrum, from coveted H1B high-paying tech jobs, to seasonal farm workers who exist in slavery-like circumstances. Both countries show significant, sustained technological innovation.

I agree this is destructive to the social fabric, and it separates us into strata. But I have a hard time believing that immigration is the cause; a simpler explanation would interpret it as one of the symptoms, with the underlying causes being closely related to the relentless transfer of wealth to an ever-shrinking "elite".

[strken]

The one I was thinking of was slavery in the US, and the technological innovation in the south vs the north.

A better example might be the low price of labour-intensive hand-picked fruit (particularly berries) in the US and the correspondingly low agricultural automation. It's not that machines don't exist, or that berry picking is going to prevent the next Facebook, it's that they aren't cost effective in the short to mid term even when longer term investment would eventually improve the whole industry. This is really hard to measure and I don't have any good sources for either side of the argument right now.

I also want to make a distinction between skilled and unskilled migration. I don't think skilled migration is harmful to the social fabric in an enduring way, nor migration with the same proportion of skilled and unskilled labour as the host country.