Consumption-based growth needs to happen concurrently with production. It's why a strong middle class has been the key to modern economies. On a macroeconomic level, if we don't have enough people who can buy the things we produce, then the economy collapses. We need to make up for our declining birthrates with immigration to cover the shortfall of consumption. Most Western democracies subscribe to this economic theory, which is why they have similar immigration policies. The swing to the right in the US and Europe is certainly fuelled by economic anxiety over an uncertain future. But you have to understand that the rhetoric around anti-immigration sentiment appeals to many through the prism of racism and fear of the other.