Someone put me in touch with the person behind this excellent Ending Activism blog. I am working my way through it at the moment – it has some interviews with people about why they got involved in activism and why they left.
I think what is rarely stated in the interview answers, but that is there if you read between the lines, is that ‘activism’ is often engaged in something like a hobby, rather than being a part of everyday life. And it is a very tiring, awkward and frustrating hobby. If your political action isn’t embedded in your life as a positive part of your everyday life – which isn’t to say you can’t be more or less active at different times – then I think it’s quite predictable that people give up on it. Life takes over.