Why unable to use 3rd party cable for charging?

This is to prevent damage to the device. Also, if you remember some months back, a woman was electrocuted due to using a knock off cable. The use of brand cables ensures the proper connection as well as charging capabilities to reduce the chance of fire, electrocution and other damage to the phone.

Firstly, it's got nothing to do with control. Apple wants it's products to charge more quickly than other products, therefore it has to provide a higher voltage to them. The reason that your awesome iPhone rejected your crappy third-party cable, is to keep you from frying your phone. Incorrect voltage management is how bad things happen, such as cables melting, or phone mysteriously stops working. If you use a third party cable, you run the risk of ruining property. Hence the warning message. Apple makes very good products, and that is why they cost more. A good apple cable is going to last four times longer than the crappy one anyways, so save some money in the long run and get a proper cord.

Or perhaps instead of spending a couple hundred dollars buying another smartphone that isn't as good as the one you have now, you could just go buy the $40 cable. Or better yet, spend the couple hundred dollars on a newer iPhone that comes with a shiny new cable. Both are better options than "I'm switching to a crappy phone because my crappy cable won't work with my good phone"

Bye.

Of course you considered the fact you may have purchased a defective cable and you need to return it to the very big electrical store and get another one? Or are you just wanting to rant?

So, the fact that you may have purchased a defective cable from the store show that Apple is trying to control your iPhone? This is a 30 pin cable?

Your charging cable doesn't work, so you buy a new phone. That is a novel approach.