I have a city of about 500,000 people. I didn't aim to make this city very functional, but I focused mainly on the aesthetic part. I've finished designing my city the way I wanted it and I don't want to expand it or make any more changes. Since I've let my city stay as it is after I've finished it, I've reached the point where the population stopped increasing and started decreasing. And my question is, if I let time keep running, will my city's population of 500,000 people continue to decrease until it drops to a much smaller or very small population? Will this affect the amount of cars I see on my streets, considering that my computer's limits support up to 16,000 cars on the road and 30,000 parked cars?

In advance, thank you very much for the help :D