The best way to get rich is to generate a large amount of value for a lot of people as fast as possible in a way that you will directly benefit on the upside (imho.) Not pinch pennies and put your fate in the hands of returns on a specific asset class.
2) 8% returns at 2055 is a bit optimistic, but not unrealistic. I won't mind if I have to adjust the date +- 10 years to time the market. I feel comfortable putting the majority of my assets in the US stock market, but I do have some assets independent of it. The last the stock market crashed substance farming was popular.
The payout on your strategy (generate a lot of value for a lot of people) is high, but the probability of success is very low. (And the payout is usually tied to the stock market, if you're talking about generating corporate equity value, private or public.)
Conversely, a dollar saved is just a dollar plus it's return over time, but the probability of saving that dollar is essentially 100%.
It's also a convenient way to justify not saving enough.
I've watched fairly successful business owners make this mistake many times - they were making 400K or 500K (in some cases, millions) a year off a business, but not saving anything because they still expected it to grow a lot larger. If it fails to grow, then end up either broke or in debt.
It's inherent to entrepreneurs that they believe in the big future payoff more than average, but that's also a big blind spot for financial planning.
Your examples showcase the pitfalls of bad planning and not the probability of business success. Success doesn't absolve one of the responsibility to plan, but being someone who did succeed can open up additional doors and options for the said plan.
The entire problem is that most folks grossly overestimate their probability of future success, even over a lifetime.
(Not to mention likely done a lot of damage to your health and relationships, if you spend a career trying to finally achieve a big outcome... there are non-financial costs to taking bigger risks that we often fail to assess.)
As for probabilities, spending 10 hours per week, thinking, and iterating on side projects, over the course of 10-15 years can bring a sustainable $10-15k monthly pre-tax income if done well. (I define well to be build stuff people want, focus on your customer, etc) If one's time horizon is smaller or income needs are larger, then there are other leverage points that can be used.
Adding to this point: Don't make your life suck today so 2050 you can live. What happens if you die tomorrow?
Strike a balance between making it rain and being a miser.
I always translate monthly expenses as 2055 dollars, because that is my target retirement date.
If something in 2018 costs $100/month that means it costs $1,200/yr. You can expect to see about 8% returns in the stock market over the long term. By saving $100/month for a year instead of spending it I will have ~$20,000 in 2055 money. If I continue to save the $100/month instead of spend it I will have ~$275,000 in 2055 money.
Edit: Translating to your target retirement date dollars also works for one time purchases.