I don't think that all of these are luck. +1 on the financial environment and potential medical pitfalls. However, being in a frugal household does not mean that you will practice it. You still had to have the discipline yourself. Putting effort and persistence into your job is not luck. Let's give ourselves some credit that we made some of our good luck with our efforts.
+1
I made the conscious CHOICE not to smoke pot or do drugs school when all of the other cool kids were
I made the conscious CHOICE not to get anyone pregnant or other things that could destroy my future
I made the conscious CHOICE to sit in the basement of the engineering building night after night at school while everyone else was out partying
I made the conscious CHOICE to work 3 times harder than anyone else at for the last 35 years when it was very easy to slack off and "get by"
DW and I made a conscious DECISION to save 50 to 60% of our income for 30 years, living WELL below our means.
DW and I made a conscious DECISION to raise our family in a 1200sqft house and not buy a $400,000 house when all of our friends were doing so
DW and I made a conscious DECISION not to fly to Cancun and the Bahamas twice a year, every year, like most of our friends did
DW and I made a conscious DECISION not to buy the latest Lexus or Mercedes like most of our friends, and instead drive Scions and Mazdas
I made the CHOICE to spend hours researching and studying investment and retirement strategies while everyone else said I was wasting my time
Every decision I (and we) have made for 35 years has been strategic and carefully-measured -- to get us to where we are now, an approach that both has protection for a minimal lifestyle in times of crisis, as well as a long-term strategy for retiring early.
Yes, luck
IS involved, but it is ALSO what you do with that luck, the choices you make, and your determination.