So yes, especially this year with all those heat warnings, miserably hot 100+ degree work floors, mandatory overtime and constant use of temps, harsh conditions are, unfortunately, quite normal for that kind of environment.
That said, just because it's normal, that doesn't mean that it shouldn't be improved. If you have to make a fuss, you should. There are a ton of people out there who simply can't afford to make waves in this economy and they're suffering for it. The people who can best afford to make waves need to if they see unsafe conditions.
You're right that they help a LOT. I think we were able to get a bunch at a dollar store for some ridiculously cheap price. I can't believe that more places don't use them.
Everything else aside, the "terrible" working conditions at Foxconn that people get so riled up about sound better then this Amazon warehouse in the US.
There are a lot of jobs where people work in these kinds of conditions. Where I live when it gets hot and the air is still it's pretty common to see people who work outside overcome by the heat to some degree.
High turnover and having lots of temps to try and make things work, even semi-permanent temps, is generally the norm as far as I can tell. And yes, it can really screw with production. Lots of people who don't know what they're doing is always hard to deal with.
So yeah, I think it was the downturn that led to people getting treated like crap, but maybe Amazon really is worse than most. I've never been there, so I don't know. I can tell you that when you have lots of temps, you will see people getting fired all the time for screwing up or slacking off. Some of them even deserve it.