I too have been brewing for a few years (Grainfather system), and do enjoy producing my own beers that are usually very good, and can compare to many micro brew offerings. Brew days for me are enjoyable and I have recently started kegging my brews, which requires a bit of acquired knowledge as well.
However, my thoughts on the decline of brewing participants MAY be due to the amount of time required for cleaning and sanitizing all equipment to insure positive and enjoyable results.
It certainly might be an eye opener regarding the time commitment required in this regard, that many new brewers may find excessive, especially with the demands of a growing family etc. And although you do become more efficient at this process over time, there is no avoiding it if you expect decent results.
Often people might start this hobby without fully realizing the overall time demands, just figuring - I can just throw a new brew on to save a few bucks..... It should be pretty easy!