Shelf life

is something I understand...and don't understand.
You know what I mean...all those "use by" dates on things you buy in the supermarket? 
I can see they are necessary. You don't want people or other animals eating food which is not fit for consumption. That's perfectly fair and reasonable. I always look at the "use by" date on items I know have a limited shelf life and, most of the time, I look at other use by dates as well. It is particularly true of things I know don't have a rapid turnover of sales or that we only use a little of and may use over some months.
Most people I know do the same.
But something else appeared in this morning's paper which made me consider, yet again, shelf life from the producers point of view. There was talk about "iced coffee" as a "milk drink"...the sort of iced coffee that is bought in packs in the refrigerated section of the supermarket - along with, in lesser quantities, "chocolate" and "strawberry" flavoured milk drinks.
There was also a perfectly reasonable discussion about the amount of sugar which is put into these things.
I don't drink these things. I do not particularly like coffee. I will drink it if it is not too strong - about a quarter the strength of the coffees made in our local shopping centre. On the rare occasions I do drink it then I do not want sugar in it thank you very much. I don't want an "artificial" sweetener either. The drink which passes for "iced coffee" in the sealed cardboard container from the supermarket is something that is, to my taste buds, like drinking sugar syrup.  I admit it has been years since I have tasted it but I am told "it hasn't changed much, if at all". The chocolate version is apparently just as sweet and the strawberry version is not just sweet but "artificial". 
No, I am not interested. Milk has natural sugars in it. Milk drinks like that should not need added sugar. Why can't they do one with "no added sugar"? It has to be the shelf life thing doesn't it?