I am an immigrant and yet I agree to the fact that getting permanent residency is a privilege and not a right. US population is around 330 millions, we don't need billions to overpopulate US. An influx of 100 million will screw up US so bad in terms of everything. I bet, given a right to be a US resident by choice, 100 million applications will be filled in one week.
Having said that, USCIS needs to improve its system as well to process certain applications within the average processing time frames.