While the arguments in favor of electric brewing in this thread (and elsewhere) are powerful, they are not necessarily exhaustive. Personally, I would LOVE to go electric*. Nevertheless:
1. The "fun & entertainment" part of DIYing a brewing setup is true for a number of home brewers, not so much for the rest of us. For instance, while I possess the skills to wire the controllers, etc. for an electric brewing setup, I have no inclination do to so. This is only partly related to #2 below.
2. Even a DIY electric brewing setup is costly. And by this, I mean >$2K. I have read threads on HBT and other forums by a number of people who confess that they seriously underestimated the cost of an electric brewery. While this may be rationalized by "I had fun," or "I learned things," this does not contradict the initial statement.**
3. Not every homebrewer brews enough to justify building or buying an electric setup. My brewing volume given the consumption of my SWMBO and myself, some to family, and the six-pack here and there in trades or gifts amounts to no more than 15 - 18 5 gallon batches a year. It's pretty much of a stretch to justify an electric brewhouse for that much beer. That may well change for me due to advancing age, but that's my situation now.
4. It should be included that there ARE homebrewers who simply don't have the electrical service to provide an adequate electric supply. I am not one of those, having 200A to the house and 100A to the garage, but I'm mentioning it anyhow.
*NB: I define electric brewing as brewing in vessels with fixed electric elements, such elements controlled by devices regulating time, temperature, the flow of pumps, etc. Rather than describe such equipment myself, the DIY version can be seen on The Electric Brewery site, and the off-the-shelf variety by the Speidels Braumeister. Therefore, I specifically exclude from my discussion (for a number of reasons I won't elaborate on here) all sorts of non-fixed "heat sticks" and the like.
**NB: I reject the "but it's cheap" arguments of those people who bought all sorts of expensive components on eBay or a garage sale for $25 for a box load. Or got them at work for free. Or found them by the side of the road. Pretend there are those of us who never seem to find these wonderful treasure-troves.