How much time did it take you to learn SAP FICO? What is the future related to the job and profile?

I have many friends working as FICO consultants in different organizations, most of them started with FI module and then got involved with costing (CO) later, they are doing pretty good

Your question took me to the past.. :)
I remember the time when my SAP ABAP training started, I was to anxious to learn and complete the training, so that I can start working on live scenarios.. (Sorry for the distraction! I'll keep this story on hold and answer your query first!)

Actually I am not part of the SAP FICO module but will give you some insight about it.. Mostly there are 3 - month training programs for almost all modules including (This varies from org. to org.):

Classroom Sessions - 1 Month
Practice Sessions - 1 Month
Topic Specific Sessions - 1 Month

Then after the training completion, mostly the employees are assigned to different projects as trainees/shadows (which mostly last for 4 to 6 Months). In most scenario's, people start working on live tickets during the shadow period and that improves their module knowledge.
Further depending upon person to person and project, I think in 1 year time, people learn most of the concepts for the particular module and rest clears out with experience and exposure.

Talking about the future of SAP FICO consultants, I think it is a good profile. As there are few people who are good with finances and when you are good at it, then future propects would be good too :)