In our busy society of today, we are constantly bombarded by countless things to do. With limited time and the ever-growing list of to-do things, we start to prioritise and a few things end up taking the backseat and eventually neglected.
We cannot ignore the benefits of learning music (http://news.nationalgeographic.com/news/2014/01/140103-music-lessons-brain-aging-cognitive-neuroscience/), even for those picking up an instrument for the first time in midlife or beyond. Recent years studies have also shown that the longer one plays an instrument, the more benefits one gain (http://www.ncbi.nlm.nih.gov/pubmed/21463047 & http://www.ncbi.nlm.nih.gov/pubmed/22833722).
We understand the demands of an adult life, be it career, spouse or kids. Then whatever free time we have we split it amongst the things that we like to do most (i.e. the path of least resistance e.g. watching television, surfing the internet, etc.)
If you are currently learning an instrument and you are a busy working adult, even dedicating 15-30 minutes out of the free time to practice will help you tremendously in your music-learning progress, not to mention the benefits you’ll slowly and eventually reap as mentioned in the studies above.