I'm a lecturer and, according to Silkei's definition, far from successful: like so many others, I am stuck in the part-time contract/fulltime workload trap. I earn far less than 30k and have to supply my own teaching and research materials a lot of the time. Financially, it is difficult because the demands made on me (e.g. to be able to go off to the US on a grant that doesn't cover the actual costs) presuppose a comfortable background.
But students of mine are going out in the world and using the skills I have given them to do interesting and fulfilling work. That is a kind of success.
The book I published this autumn is a good book and unlikely to be replaced any time soon. That is a kind of success.
I have plans for work that seems to me worthwhile and that will keep me interested for the rest of my working life. That is a measure of success.
And I do have colleagues who have been far more successful than me (very nice people too!), so it is clear that success- financial and academic is possible, even though the climate is not very positive at the moment.
Looking at it dispassionately, I would say my own lack of success could be divided into two separate fields:
factors beyond my control (foreigner with no contacts & wrong educational background, many years as carer of disabled child, health problems)
factors which I can still do something about (willingness to step out of my comfort zone and accept that new skills and new ways of thinking may be required, more planning ahead, more assertiveness in demanding new roles, less self-effacing, greater singlemindedness)
I have yet to meet an academic who feels they can take 7-8 weeks holiday, though.