According to my understandings, the Islam forbid all drinks consisting alcohol strictly. However, i don't know more about coffee and tea

Shukran, islamispeace. I will respond more later in the debate.

Shukran, islamispeace and abuayisha. Allahma3k. 

Islam was completed in 23 years.
The very first revelation were five verses that said there is One God who created man, and taught him knowledge.

From here began the series of revelations that continued for 23 long years, till the last verse and the religion was perfected.
During these 23 years the politics and culture of people also developed around the teachings of Islam.

Since alcohol was a predominant part of arab culture before Islam, it was not the very first thing that was dealt with. The very first thing that needed to be corrected was idol worship.
That worship is due unto One God was the primary object of the message.

People do not change overnight, and the Creator knows this very well. Thus He did not command them to do so either.

Like so many practices were revised step by step during the making of islam - so was the ruling for alcohol.
For instance arabs were accustomed to marrying several wives, frequently divorcing and taking new ones, leaving some of the wives unattended and uncared for, yet not released so they could find another partner. Islam brought a check on this.
Arabs used to take bond men and women - Islam abolished this practice.
Rights of inheritence were layed such that daughter got a share in father's property.

If Allah wanted He would have handed the entire Quran all at once, but His wisdom in sending it down gradually can be understood by the fact that it would have been a huge burden on anyone to suddenly leave ALL they were accostomed to and acquire a new code of life.

This points us at another fact that when a new convert enters Islam, even s/he is not required to leave everything of his former life overnight to accept the ways of muslims. They are advised to take things one at a time.