There are reasons some of these "pre-built" programs are so popular, Some of them work VERY well. Typically what happens in a lot of cases is the person doing the routine becomes impatient and doesn't see the progress they think they should, or in the time they think they should. So they start throwing in a bunch of isolation movements thinking that more must be better. In most cases this leads to further frustration which often times makes the person give up thinking that they can't acheive the body they want. Or overtraining and injury. You're right to stick with compound movements. If you are pushing yourself to failure you're getting a good workout in. Give it some time. It takes more than a few months.