The economy probably cannot grow faster than slow because of demographics. From the 1950s until very recently, population growth of the prime producing years of the population grew. Now it has flatlined, actually down a little. And it is going to decline significantly. So the tail wind is now a head wind.
The economy is the addition of population + productivity. You would think it would be ok to have the population decline because the economy per capita remains the same. I think it fool hardy to import millions of low skilled and hostile people to keep the absolute data (total economy) of the economy growing. Importing them does in fact add to the population in the formula above. But they reduce productivity so we are no better off for it.