The steel that we use for just about everything from cars, trains, automobile parts etc comes from the ground which is mined as Iron Ore.
The earth contains lots of Iron Ore that can be used for thousands of years yet.
It could be possible for the world to eventually run out of Iron Ore to make steel and then we might run out of steel eventually but it would likely take at least 500,000 years or longer of mining Iron Ore before we completely ran out of Iron Ore.
However since Iron and Steel is a recycled metal that gets recycled a lot then it's unlikely we would ever run out of steel.
There's plenty of steel and Iron left in the world even though it's used a lot.
Right now steel and iron ore is cheaper to mine than it is to recycle so that is one reason that scrap iron and scrap steel prices are down right now.
Eventually the scrap iron and scrap steel prices may go back up if it becomes more expensive to mine the iron ore.
The earth is made of iron and steel ore along with other types of metal.