This is the correct answer. Sure you can work smarter; sure, you can come up with superior ideas; but time is almost always the limiting factor in execution.

It's unpopular to rally against the cheerleading "you can do it!" crowd here, but the reality is that you've made a choice to have a family, and that choice carries some consequences with it. Some people who have families choose to pursue their work above all else anyway, but this approach often carries the cost of divorce, resentful children, and some degree of social ostracism.