I live in south Texas, where the temps can easily pass 100 every day for over 3 months, and that's just the most dramatic part of summer. And I go for a daily walk; even going at the 'cooler' times of the day, it's in the high 70s/80s/low 90s w a lot of bright sunshine. However, I don't consider my hot weather clothing disposable. I buy woven tops & dresses rather than knit (I do not want *anything* touching me when I'm hot) in fine cottons or cotton/silk blends or silk (I have a couple linen/linen blends too that are fabulous & I'd like to add more). At the end of the day, I turn the top/dress inside out and hang it from a hook over night. In the morning, if it smells at all, I put it in the laundry hamper, but you'd be surprised at how frequently there are no smells! The key for me is to make sure the armscye isn't too fitted: as long as the fabric isn't squished up in my armpit, I don't usually have a problem with sweat stains or odours (and I tend to sweat a lot in that region in all temps, unfortunately). And, at the risk of further TMI, I've noticed that the 'cool off' sweating I do in summer on say my back or belly doesn't smell/discolour the way armpit sweat does. 100% silk can be problematic: it seems more prone to armpit problems. So I usually stick to blends in the hottest months or sleeveless tops that are nowhere near the 'danger zone'.
My shorts & lightweight trousers are as sturdy as their cooler weather counterparts. I also wear a lot of cardigans in the summer & these don't seem to wear out much quickly than my fall/winter ones. But I have an extensive wardrobe, so I might only wear each cardigan once a week, which is of course going to be a factor. I have a lot of summer weight blouses too, so ditto as far as them not seeing terribly frequent wear. I've travelled with some of the blouses, when they form part of a tiny capsule & get very frequent wearings, without seeing a problem.
I guess what I'm saying is that there's hope for you to buy some quality tops that will last for a decent amount of wearings, as long as you look for wovens instead of knits & looser cuts. Although of course you mileage may vary!