It's certainly possible to produce your own music - and video - by yourself. What you do have to have - and no amount of equipment will do it for you - is an ear for what sounds right and how to get the best from the instruments/vocals being recorded. Sound studio technique is an art, like anything else, and a good sound engineer can make the most of the raw material.

I do my own CD and DVD recordings - and sell them in small quantities - but I don't care for the quality of the stuff I first recorded (and didn't sell). It's taken many years of trial, error, experiment and practice to get to a point where I think what I do is half decent. Your friends sound as though they're quite clued up and can do a good job. Not all musicians can do the same - and that's where the sensitive sound engineer can help. Mind you, I've also known some crap sound engineers and producers...