Project B is a hard tech project, which I'm unqualified for, by a long way. Will take years and years of work, but will be the coolest thing I ever work on. Possible success rate = (0.0001)
Which do you pick and why?
If you are a trust fund baby, pick the one that's the most fun.
If you have to feed your family, pick the one that's most likely to get the income.
Success rates like 0.0001 are essentially made up.
Assuming self-funded, option #2 means a potential earnings loss (compared to employment) of at least ~50K/yer * 4 years = $200K. That means your projected expected earnings would need to be $2 billion.
It's even worse if "0.0001" means "0.0001%".
What's the probability of success in doing A and then doing B, given that doing A likely gives you the experience to help do B?
One thing that I've realized as a procrastinator, is that being an ideas person is very overrated and it's very easy to inflate the future value (financial, emotional, social) of ideas.