Telecom is one action packed industry to have replaced FMCG as the mecca for sales and marketing wars.
Mobile telephony in India started with something slightly less than a whimper. The indiosyncracy of the Govt. made it sure that the revolution did not spread to the masses and companies continue to invest in the hope that the dark clouds of regulation would give way to bright sunshine some day.
Telecom is a very technology intensive industry compared to FMCG where if you market well your product sells well.
Let me start with ennumerating the stark differneces between Telecom and FMCG 
(though most of these differences are applicable between telecom and almost every other industry)
1) The FMCG product one buys is really not measurable in terms of advantages it proclaims to offer.
That is to say one can really not measure:-
the extent of 'Tazzgi' offered by any soap,
the improvement in health of their children by eating certain ayurvedic products,
the improvement in height due to drinking health drinks
the safedi ki chamkar offered by one detergent over the other
now all these products would seem to be satisfactory of unsatisfactory over a period of time to any consumer but the exact measurement is really hard to come by. Meaning that in the end what we end up purchasing the next time we go to the retail outlet is mearly based on 'Perception'.
On the other hand the SIM that one purchases would either give you a very good signal or not. The strength of which is again measurable by anyone, anytime, anywhere. One conversation over the network and the voice quality would be known to the consumer. One wrong billing and it can be tracked as soon as the call ends.
The telecom product makes itself vulnerable to measurement at every instant of usage.
2) The product in FMCG is 'sold the moment it is sold', in contrast the real telecom product is the 'airtime' which is only expected to be sold once the dummy SIM has been bought by the customer. Thus while sale of each unit of one bottle of 'drops of happiness' fills the company with happiness, but, the sale of each SIM only leave the company further more anxious in anticipation of the actual sale that needs to happen.
3) FMCG products, because they are sold on perceptions can do wonders with marketing (which obviously needs to be supported by sales and distribution), which in turn means that Brand Loyalty can be built with fair amount of effort. The telecom as we see it has seen minimilistic Loyalty because it is a price game. Thus while FMCG has price loyalty built across all income stratas, the only strata that tends to shcow Brand Loyalty is the affluent ones who do not care for money and in most cases it is the Customer Lethargy rather that Brand Loyalty which makes people stick to a telecom operator.
4) In telecom the customer is literally purchasing the product after every
single usage - which is actually in terms of seeing how close is he to recharge is accnt. Okey what does this actually mean? This is to say that every time the customer has used the services he has depleted the amount by which it can be used furter (which is true for every FMCG product as well) but this depletion is 'Clearly Visible'. Let me put it this way: when was the last time you had a bath and looked at your soap and felt 'Boss nahane ke pehle 50gm tha abi 48g hi bacha hai'. That's it, this is what is actually possible with telecom product - about 90 - 95% market in India is Prepaid, which shows your balance as soon as you end your call.
Thus when one gets a feeling that one is spending on a product 10 times each day then he should make the most judicious financial use of it, which in turn makes it a pricing game more than any other industry.
5) Telecom product is amazing in another way, you need to have a distribution channel but the channel is nowhere similar to your traditional channel. The inventory here needs ZERO SPACE, compared to any other industry which needs place to stock the the goods. The only space required for SIMs can be a small bag thus one can actually operate standing on the road side and still be the biggest retailer of telecom products in the town. Now how's that for a thought :D
6) A telecoms product usage is completely controlled by the company even after the real product is sold. In FMCG a company can not control whether its ‘Sitaron ka Sabun’ is being used for bathing, washing clothes or by some psychopath to scrape slices with a knife and eat along with bread. But in telecom, even though the customer has bought the real product – airtime- but the usage is controlled by the company. The company can completely monitor with whom you are speaking, what you are speaking, what text you just SMSed, whether you can make calls on a particular network or not. In all everything you do is at the mercy of the company. Which brings in another stake holder that is the Government, which can ask for any details anytime about any activity done by a particular person.
7) There is a huge interdependency among the competitors not seen in any other industry. Does Pepsi really care what Coke is doing than just making it sure that it needs to beat it in the competition? Nops. But in telecom I need to make sure that the call starting from my network is properly diverted and taken by the competitors network so that my customer is not irritated.
Let me give an example here: Say I am a new telecom player, with not so great financial muscle as my competitors, though I give excellent services and great voice quality. Now as I am new, I will have a very small customer base and most of the calls from my customers would land up on competitors’ network. This is where all the fun begins, if the competitor wants it can bar calls from my network and all I will get to hear is ‘Aapki call abhi puri nahi ki ja sakti hai, kripya thodi der baad call karein’, and once you call somebody else and get the same response you are certain to throw your SIM. Finally you go back to the old players cursing the new player.