The question is indeed, as you hinted, if those limits are largely self-imposed or not. There are certainly some external penalties, but what really keeps me up at night is the fact that past performance is a huge indicator for future performance. If I want to set out to accomplish anything of scale, I feel I have to delude myself into ignoring the nagging feeling that if nothing ever came out of anything I did in the last 20 years, it's more than likely the next (and also last) 20 years will be very similar.