Automation alone will never make cheap labor completely irrelevant. This is basic economics. In absence of external regulations, automation and job streamlining effectively increase supply of labor, causing its value to drop. As long as price of human labor can freely decrease, it'll simply drop to a point where hiring a human is cheaper than buying and maintaining a machine. This is exactly why cheap t-shirts, for example, are made in Chinese sweatshops and not on robotic assembly lines. Remember, industrial machinery cost a lot of money up front and requires maintenance as well. Upfront costs of hiring unskilled laborers are near zero and maintenance is entirely dependent on how much money you're willing to pay them (and government regulations).
Does it really matter where terrorists recruit? In modern times, the physical location of terrorist training and recruiting grounds doesn't seem to matter much. If you look at recent ISIS-related terrorist attacks, the perpetrators generally traveled to the location of the attack. Closing the borders won't decrease the overall number of terrorists (might increase it, as a matter of fact) and will not put a significant damper on ISIS-style terrorism. It might change their focus, but I don't believe it would hinder them. It's important to note that international religious terrorism is a new phenomenon, only tangentially related to earlier terrorism cases like IRA.
Generally terrorists that fight "close to home" are of a different kind, fighting for a well-defined goal of independence or rights for a particular location. You don't see Hamas blowing stuff up in France or Britain, because their beef is with Israel, neither did IRA ever struck outside UK (to my knowledge). This is a different kind of problem, different kind of terrorism and its
always regional. Concerns about Arab communes coalescing into mini-nations that could then try to establish legitimacy are far-fetched and could be prevented by dispersing immigrants to prevent such communes from forming (not that democratic countries would ever do that, either).
That's not so much a problem with that form of government as it is with the entire populous no longer having the time and / or inclination to actually be concerned with matters of state, exacerbated by clickbait media - not literally *click*bait for MSM, but still all they want is the $$$$ and sensationalism, not in-depth reporting generates that. Although that also directly feeds back to the populace wanting and rewarding that type of media, because they no longer know any better.
Did they even know any better, though? Sensationalism isn't exactly a new concept. I think that the problem is that misleading or even outright fake news were made easier by internet lowering the financial barrier to entry for news providers. To run a newspaper you need, apart from news themselves, to pay for a printing press (big ones are expensive), paper, ink and delivery people to get it to the stands. If you want a lot of people (like an entire state, nevermind the nation) to read your newspaper, those costs can be very large. For large-scale radio broadcasts you need to buy a decent-sized transmitter (also expensive), power for it and have a channel allocated. TV is similar, except you also need a fully-equipped studio. Running a news site on the internet, though? Just buy a web address, download a premade "news site" template and you've got yourself a news page that the entire
world can read. You can write anything short of outright libel and quickly make up your investment with on-site ads, so there are no regulations, no reputation to uphold and no consequences to presenting outright lies as "news". These days, stories of that sort come faster than Politifact can debunk them and what's worse,
anyone can write and put them up.
Common people were never particularly involved in affairs of state. They read the news and voted based on what they read. However, in the old days, they only had a handful of newspapers to choose from, which were big and had a reputation to uphold, so their articles were competently edited and verified. A candidate could make long-winded speeches all he liked, but if the newspaper printed it side by side with an article debunking every single statement, it wouldn't get him very far. The media used to serve as a filter between politicians and the general public, which probably helped limit attempts to game the system and kept the US democracy working for about 200 years. Now the filter is effectively gone and it seems that politics, both in EU and in the US are rapidly deteriorating.