The lack of consistent power is another liability. Bad sun days, low sun in winter, and of course night. So you need storage batteries. Their storage capacity is good for very low consumption applications but to get enough batteries to store as much power as a normal home consumes is quite expensive let alone the cost (and size) of panels to do it. Solar cells may last decades but the batteries will need to be replaced.
Not that solar installations aren't great. They can do some specific jobs really well. If you work hard at understanding your consumption and keeping it low you can get a very useful system.