Why does iPhone 5s have so many different models for GSM and CDMA netwrok? Very confused? I am quite confused about GSM and CDMA models of iPhone 5s.

Please read this in Wiki http://en.wikipedia.org/wiki/IPhone_5S:


Connectivityof iPhone 5S

List All models:

GSM model (A1533)
LTE (Bands 1, 2, 3, 4, 5, 8, 13, 17, 19, 20, 25: 2100, 1900, 1800, AWS, 850, 900, 700c, 700b, 800 MHz, 800 DD).

CDMA model (A1533)
UMTS/HSPA+/DC-HSDPA (1700/2100 MHz), CDMA EV-DO Rev. A and Rev. B (800, 1700/2100, 1900, 2100 MHz), (except China model:)LTE (Bands 1, 2, 3, 4, 5, 8, 13, 17, 19, 20, 25: 2100, 1900, 1800, AWS, 850, 900, 700c, 700b, 800 MHz, 800 DD).

CDMA model (A1453)
UMTS/HSPA+/DC-HSDPA (1700/2100 MHz), CDMA EV-DO Rev. A and Rev. B (800, 1700/2100, 1900, 2100 MHz), LTE (Bands 1, 2, 3, 4, 5, 8, 13, 17, 18, 19, 20, 25, 26: 2100, 1900, 1800, AWS, 850, 900, 700c, 700b, 800 MHz, 800 DD).

GSM model (A1457)
LTE (Bands 1, 2, 3, 5, 7, 8, 20: 2100, 1900, 1800, 850, 2600, 900 MHz, 800 DD).

GSM model (A1518)
TDD-LTE, TD-SCDMA[6]

GSM model (A1528)
LTE (unofficial)

GSM model (A1530)
LTE (Bands 1, 2, 3, 5, 7, 8, 20, 38, 39, 40: 2100, 1900, 1800, 850, 2600, 900 MHz, 800 DD, TD 2600, 1900, 2300), (with software operator version China Mobile 15.6 or above:) TD-SCDMA


Why doesn't Apple make iPhone 5s to be "world phone" like iPhone 4s. World phone means it can use for any network in the world whether CDMA or GSM.

If they can't make Worl Phone, then at least they should create 2 models only. 1 for GSM &amp; 1 for CDMA.

However, surprisingly, iPhone 5s has so many different models. It has 5 different models for GSM? 
so 
Does that also mean 5 different iphone 5s with 5 different hardwares?

Likewise, it has 2 different models for CDMA.

Why it has so many different models for the same network. Before that they only have 1 or 2 or max 3 models (iPhone 5).

The big question.

What if you buy the wrong model (even for the same network)? For example, I am a user &amp; I just roughly know that my carrier using GSM, then:

How do I know which model (A1533, A1457, A1518, A1528, A1530) to chose?

Very confused? or Apple is trying to confuse the ones who buy the unlocked phone so that they can make more $$ from contract with carrier?

How to make sure I buy the right one.
This is only a problem if you are buying the phone (unlocked) in another country from the one you want to use it in.

If you are buying the phone in the same country that you intend to use it, then all you have to do is see which model of phone is sold by the carrier with which you intend to use the phone, and then buy that same model.

If you are in a different country, ask someone to visit a shop in the country where you intend to use the phone, and check the models sold for your intended carrier.

I suspect that the real reason is not to somehow punish and confuse potential customers (they really don't want you to buy the wrong one, despite how it feels to you now), but is more to do with available chipsets for the various LTE bands.