Why mobile brands like Karbonn, Micromax, I-on etc are cheaper than Nokia, Samsung...etc?

Mobile handset business is on its high in recent years. We find new mobile brands entering market every day and more than 90% of phones offered by new companies are dual sim phones. They provide handsets at a cheaper rate than the older brands (like Nokia, Samsung, Sony Ericson etc...) and hence are attracting the consumers. But, I was wondering how do they manage to give mobile phones at lower cost? Here are the few facts which I felt may be the reasons for the lower cost.

1.       Quality of the parts and finishing of the handsets:  This is not a major reason as most of the cheaper phones come with a warranty of 1 year or more ensuring good quality.

2.       Advertisement:  The advertisements given by the top branded manufacturers add up to the mobile cost. Nowadays, cheaper brands have started giving advertisements but not in a large scale.

3.       Size of the company: Newer entrants have less number of employees and offer lesser salary to them compared to top brands.

4.       Service and support: Top brands set-up exclusive service centers in major cities which is an extra burden on them. Even though newer brands provide service, they just make agreement with local repair shops and call them as authorized service centers.

5.       R & D: Newer brands don’t concentrate much on research and development. This is very important in terms of making the phones more userfriendly. Even though these phones have all good features, they lack userfriendliness which is one of the reasons which makes them cheaper.

These are the reasons which I found out. If you have few more information to share with, please do it in the form of comments.