“This is what I don't get: the UK already DOES decide who settles here! Admittedly only indirectly, but if we are talking legal migration here, then it's basically as follows: healthy economy - lots of migrants. Unhealthy economy - fewer migrants.
I know which I prefer.”
Even accepting your (very iffy) contention that the UK controls its immigration by the controlling the state of its economy, ikky, your logic does not quite stack up. The health of the economy and the need to accept uncontrolled immigration are not conjoined. Furthermore, if the state of the UK’s economy declined it may, but not necessarily would, result in a reduction in immigration, especially if our economic decline coincided with decline in the countries of origin of the immigrants. Even more than that, the effect of immigration does not extend solely to the economy (and it is not all beneficial even to just that). It also extends to the wellbeing of the country and it is quite clear than unlimited immigration is placing enormous strains on essential services such as healthcare, education and housing. Not all immigration is bad and neither is it all good. What is needed is control to sort out the wheat from the chaff and that is what has been lacking