There was 1.5B when my great-grandparents were born (1898), 3.7B for me (1971). Now there are 8.1B souls, better off economically and consuming to match.
Don't tell me we have enough food, "if it wasn't for evil peoples!". Don't care, we don't have enough water. We're draining aquifers that took 1,000s of years to fill, major cities are basically out of water all over the globe. And that was before AI!
Immigrant hate? Overpopulation. As a kid, most folks looked like you. By middle age, the world is clearly shittier, but the economy was on an upward trajectory for great-grandad, grandad and dad, but not for you. You look around today. Suddenly there are shitloads of poor people who don't look like you! See how that works? (I don't think the haters understand this.)
Global warming? Did I mention people are far better off and wanting their share? Global poverty rates dropped through the floor. The newly "rich" want to enjoy the life the rest of us had. Can't blame 'em. Look at China, still building coal plants to get "caught up". Remember the crazy smog in their major cities? LA was like that when I was a kid.
Hell, even the billionaires wouldn't be so rich and have so much influence if there were half the people to get rich off and influence. Orgs like FB and AWS could not exist as they do now with half the customers, scale wouldn't be there. If I could get one penny off every human, once a year, I'd be making $81,000.
Best part? Depopulation and deflation are economic disasters. Don't know of a time in history where we successfully navigated depopulation in the short to midterm.
EDIT: Forgot to add! We've lost 74% of the animals on Earth since I was born. That's on human activity, and lately, global warming. Our ecosystems are crashing, and unrecoverable in some cases. As one example: There are too many humans who don't want bugs around. If you're 40-50+, you knew a very different world. Hell, if you're 30, I can show you ways the local ecosystem has crashed out, ways you'll remember. "Oh shit! I forgot it was like that!"
Guess I'm wrong. We just need to allocate food, water and wealth fairly (which has rarely if ever happened). Stop pollution in the form of CO2, plastics, herbicides, pesticides etc. All while elevating the way of life for 8B, soon to be 9B, humans. Oh, and every tribe, counter to our entire history and evolution, should suddenly love one another. And somehow, we magically stomp out the wealthy. Super simple stuff! Easier than saying, "Maybe there's too many of us?"
I have my eye on Japan. They seem determined to see depopulation through without immigration. They're going to be the test case on navigating this mess.
Yes, the obvious near-term solution is taking in immigrants. But those stubborn bastards refuse, so let's see how they play this.