I've had my Fjällräven backpack for 8 years with more or less daily use for a large part of that lifespan. It could do with some minor repair, but it's largely still going strong without any maintenance
I have a pair of their normal length pants and they are probably on their 7th year. No repairs needed yet, even with around 3 wears a week. These are heavier duty than some of their other models.
I had a pair of lighter summer pants that only lasted a few years before the zipper became a problem.
You’d probably have to look at workwear to find something comparable to dickies, as dickies used to be workwear. But I feel you, I love my dickies shorts too and hope they last forever as I’m not going to buy new ones.
The athletic/weightlifting style shorts from decathlon are peak. Lightweight and stretchy where you need it.
I've had dickies but after decathlon I can't go back. Sure maybe they won't last 15 years but 3 seems reasonable for a nearly every day wear for me. And they're still going.