Some of my reasons may be specific to where I'm from, ie down under.
I began appreciating quality items way before my colleagues/friends did, almost like art. it's just that most items turned out to be designer items.
I loveeeee the smell of premium leather (not the only reason to buy them of course lol)
I'm not big on jewels watches etc and dress very casual (as most do in Australia) due to our sunny warm weather. An expensive bag is a nice way to spice up any outfit.
I work in a corporate environment, it's "within my element" to carry designer bags and wear nice shoes, nothing out of ordinary.
I dislike wastage? Even if I sell a designer bag at a loss, at least the bag is rehomed and loved again and not contributing to landfill whereas a cheaper bag will be, mostly because it's already broken/ripped.
In my country after sale service and repair for less expensive bags is pretty much non-existent and the exchange/refund policy of most stores is very limiting. Eg I can get my lv items easily repaired exchanged or refunded with no questions asked. Contra my mother once bought a furla wallet, the zipper broke after one use and the store can only provide credit note instead of refund, that's just unacceptable imo. (I have no idea how they can get away with that and if it had been a more expensive item I would've spent more time complaining!)
There's lesser choices of nice leather bags and contemporary designers usually have a higher markup and usually take a while to go on sale (which I'm just too impatient to wait and even if I did my preferred color/style would be gone by sale). Eg it no longer make sense to get a
coach for $1000s aud when you can get a couple hundreds and get lv, with the latter having so much better resell value. (Coach is declining popularity here)
The preloved market is small and usually with a high premium due to our high labour/storefront cost in Sydney, so I'd rather visit the store and get them brand new with warranty.