Well, for me in most cases the answer is no. BUT, I am mostly a freelance modeler, and I like to build or kit bash (or RTR bash these days). So I can usually find/build what I need without the high price of brass.
I only have two pieces of brass, and have only owned one additional piece in all my 40 years in the hobby. But I have worked on more than few for others.
Durable - well yes and no - repairable is a better term. They wear out, break, have problems, etc. like anything else. But, the nature of their construction does allow them to be repaired in most all casees.
Admittedly that is not always the case with mass produced plastic and die cast locos.
As for brass rolling stock, too rich for my blood when I can just build it. And with what’s out there in plastic today - why?
The two brass pieces I have are USRA light Pacifics. My roster needed them and no good quality plastic one has EVER been offered (why is that?). But my brass ones now have plastic tenders and have been reworked and detailed a bit, as older brass often needs.
Now, if brass is the only way to get the stuff you want for your prototype, and you are willing to spend the money - go for it. But don’t do it as an investment. Much of the used brass on the market as we speak is being sold at fire sale prices compared to what it was bought for. The market for most of it is way down. How do you think I got two USRA Pacifics - one was $200, the other only $100. And the $200 one is a real nice PFM.
One other point, detail for detail, a good model is a good model and properly painted no one knows what its made out of - except the owner. Much of what is out there in plastic/die cast is BETTER detailed than a lot of older brass.
I’m not anti brass, I just don’t need it meet my modeling goals, so I would rather spend my money elsewhere, especially since I like to build models, not just buy and run them.
Sheldon