I might respond to this as an immigrant living in France.
Well they are imposing restrictions, you just don't happen to notice it. In France, the amount of income you should be justfying to prolong your residence permit keeps increasing each year, not with a lot of margin, but it does move up.
By the amount of income, i mean the monthly income that you've stated to produce in or bring into France. This is checked by the state officials by accessing progress receipts of your bank accounts within the three months of your application, that is you apply to state for prolonging your residence permit, they give you an appointement three months later, and you are suppose to bring in the progress receipts of your bank account for the three months that had passed between the application and the day of appointement. This way they determine if you have a steady income for living in France.
If you are doing studies, you are also suppose to have a letter from your professor, stating whether you are doing well or not. The state officials also reserve the right to interrogate you on your subject of study even with the existence of a letter from your professor.
Depending on the type of your residence permit, there are also some additional taxes you need to pay to prolong it. This prolonging your residence permit thing usually takes around 4 months and you are suppose to apply for the next appointment 3 months before the deadline of your residence permit, which gives you around 5-6 months of hassle free legal stay in France. If this is coupled with the regular dorm policies of universities, that is not letting foreign students stay during the summers, this hassle free period is down to a little above 2 months. For my case this has been going on for 4 years, i'll move out of my room in the dorm 9th time now, that is i'll take everything that constitue my personal life here and move out from the place i'd been living for 4 years, 9th time now not because i want to but because i have to. Please do take a moment to consider that. This also imposes restrictions on what you can or can't buy. For example you can't buy a hoover to clean your room, because you can't take it with you when you are leaving at the end of the scholarly year, etc.
I am doing my phd in application of artificial intelligence technologies to ancient languages, like greek, ancient egyptian, and so on, and i remember myself trying to explain what an algorithm is to a state official, who happened to doubt the authenticity of the letter of my professor, or once a state official told me, i quote "you have no money sir, you can't live in France".
If i may adress your question directly, though there is also a material increase in the restrictions imposed on us, the major leverage of the state against the immigrants is the creation of instable juridical positions and keeping the immigrants in that state in long periods of time, this fluidity of the juridical position has an effect in almost all the parts of my life, like applying to jobs, like enrollment to schools, even something minor as opening a bank account, or buying a sim card for a cellphone. Don't get me wrong it is not that i can not do these things, the thing is the time frame of these actions depend heavily on the date of the result of the administrative hassle.
To cut short, to resist to immigrants the governments don't have to do a thing, and that is exactly how they are resisting to immigrants, by letting them fluctuate between different juridical positions for long periods of time.