Honestly, I think you should have stayed and keep working hard. With fewer competition and obvious competency, it was more like an opportunity than an unfortunate situation...
I understand what you say, but in truth the rewards available for hard work in this arena would not really have suited me. I do not want the responsibility of a higher position, especially since I see that many well qualified and motivated people are unable to keep up with the pressure. I like my life simple, so I have moved on. Actually, I am well pleased at my new position and although it is the virtually the same job, embedded organisational differences mean that the pressures and frustrations will not be the same.