None. At our current efficiency levels, 1T of us would destroy our home planet's ability to support ourselves in a week.

If we want to go multiplanetary and support populations of that kind of size, we have to get much better at optimising our footprint. Which probably requires ethical/philosophical innovation as well as hard science/technology. What we have now is too wasteful and inefficient to scale up in that way, indeed so much so that it risks poisoning itself before it's able to develop those capabilities.

You're presuming that Einsteins are born and destined to greatness regardless of their environmental conditions. What if Einsteins require particularly social/environmental conditions to reach their full potential and furthermore, what if those particular conditions cannot arise when people are packed together like sardines in a can?

This statement ignores a ton of other factors, and provides a particularly poor example. What did Einstein do to alleviate hunger? Most of his contributions remain theoretical or applied to things that don't directly help the population (or haven't paid off yet).

Even if you have someone who is intelligent, will their contributions actually make life better for people? Or will their ideas become commercially corrupted and be used for greed (Edison commercialization vs Tesla gifting)? Will they complicate our lives or provide harm along with some benefit (social media, TV, etc)? At such a small rate of the population (using your 1/1 billion), would a truly good idea gain traction? Maybe the idea to eliminate or restrict meat is theoretically a good one. But are you going to convince all the people to support it? Then how much impact will it actually have?

There is no magic solution nor hyper intelligent person that will save us.

GPS has helped a whole helluva lot of people!

But has it helped with living conditions like food and shelter? Sure it's made life easier, even for stuff like tractor positioning for field planting. But I don't see it having a real impact on those sorts of issues. I guess it has made many munitions more accurate and reduced collateral damage.

Getting vital supplies to remote areas is no small thing.

And how does GPS make that possible when things like maps have worked in the past? It just makes it easier.

Not just easier, but faster.

Have you tried moving through a desert or a steppe in the dead of night, far from human infrastructure? It's damn dark, the land is literally darker than the star-strewn sky. Headlights give you only so much light, for the next 100-150m of the road maximum. Unless it's a really nice, well-maintained road, with reflector posts, etc (and usually it's not), it's really easy to lose your way if you drive a tad too fast. You either crawl, or choose to camp and wait until the morning light.

With a GPS map, you can proceed much more confidently. And a few hours may play a serious role in disaster relief.

I'd say cars or helicopters are what makes it faster. Even in land vehicles you can use time/speed/direction navigation.

A GPS can guide you to a pinpoint in a featureless landscape where there is nothing to follow on a map.

So too can the stars, or proper time/speed/direction navigation.

I'm not saying GPS isn't useful. I'm saying it hasn't had a life changing impact for the masses that allows for a larger population (eg it's not providing more food, shelter, etc).

You need to medevac a hiker in a remote valley now and your plan is to wait until nightfall and have someone try to navigate by sextant?