There are many ways.
So first there are luxury jeans. Not going to expand on these since the name explains it all. For 1000$ you do get a very premium product.
Then there are e.g. all the japanese brands : Momotaro, pure blue japan, samurai, studio d'artisan, evisu, etc.
Pretty much all the japanese jeans are made out of denim that has been fabricated on very old machines.
Why ? They have a lower yield (which partially explains their price) and also they do create very interesting denim variations that the more efficient machines used by fast fashion are not (yet) able to reproduce.
They are also very well made with lots of more or less useful details. E.G. customized rivets with the brand logo are very nice but not something only the wearer will see.
With use, these jeans fade and are truly beautiful. It is fitting that many japanese brand do this, it is very wabi sabi. To be clear, while the construction and fit are very good, it does not make a 200$ jean magically last twice as long as a 100$ one. However, they come in a variety of fabric density, most of which are way heavier than what typical fast fashion offers. The jean will still break over time at its main pressure points, typically in the crotch and at that point it is expected that they will be mended.
There are also pants made of technical materials, like e.g. what outlier is doing. These are truly awesome to wear when it rains : they are breathable but repel water.
All of these are roughly in the $200-400 range but often closer to 200.
Then, you can also go to levi and they will make you a pair of denim tailored for you. It will roughly cost $500.