Most people by nature are not comfortable leaving their comfort zone .... so they get stuck in a rut and can't see anyway out .... only a major occurrence can cause them to leave it and venture out into the great unknown ....
Yes confidence plays a major roll in the way we look at life and make our choices .... having confidence in your own ability to make changes out of your comfort zone ..... whether it be right or wrong ..... will go a long way in developing this confidence ....
I think 98% of us have experienced this change when we left the comfort of another OS and moved out into the great unknown of Linux .... a totally different experience than what we were used to ..... none of use were born knowing how to use Linux as we weren't using that other OS .... we had to learn ....
Something or someone made us take that leap into the void .... and some will succeed and some will just give up .... maybe due to their lack of confidence or lack of commitment or the reason for their switching wasn't strong enough for them give up the comfort of their other OS ....
There may also be other reasons such as job or career related requirements so I'm not sure using an OS is the best example but it was the first one that came to mind as it is the last thing that effected me personally .... just my $.02 worth ....