Thanks for the response, my thoughts/ comments:
Agreed, does retiring in my 30s sound great - theoretically yes, but does having something to do that I enjoy and feels like I'm contributing sounds better? yes. Do many of those types of contributing activities pay, yes. Does not withdrawing anything sounds nice, yes.
After enough conversations with self employed people - at least in my local network - I've come to realize these are not exaggerations, but are truths:
Local business owners and/ or self employed people often have:
1. Multiple months of "vacation allowed" per year, write off a work truck, live in a respectable house, and still buy groceries over the winter when taking time off (while I'm at my desk job).
2. Scalable incomes, quite often >$75k / year. Quite often > $200k / year
3. No boss
I've realized I need to just play a different game. I still have motivation to work some of the time, just not all of the time that I currently do.
Theoretically, owning a business sounds great, but I really want a flexible lifestyle. I don't want a demanding business that requires me to be there >40 hours per week, even if it pays $500k / year (not unheard of in business ownership).
I don't plan to discount my rate or prices. I will be selective on the clients/ customers I work with, which may result in an above average rate. I'm an engineer, I can nerd out and become the "expert" if motivated.
The $100k = 4% of $2.5M. Exactly. I don't have $2.5M in investments, I also don't have my dream forever house. I'd love to buy a ranch style house bordering public land (not cheap).
If I was self employed working a "fun job" 3-4 days per week, with a 3-6 months off per year, dropped my savings to 10%, and never touched my current investments. Isn't that THE dream?
Something engineer-y does sounds like a smooth transition. My sticking point is the billed $/ hr rate of engineering work and the marketing needed to obtain projects. Some of these other jobs/ businesses make money on equipment and materials, so you're quite often earning >$200/ hr (ignoring equipment costs).
I have no problem investing $20-75k in equipment that "buys" me a job that could pay $100k/ yr, $200k/ yr and give me 5 months off a year.
Just trying to figure out which niche is worth investing in equipment. My gut is that "anything" would work, and I should just pick something and do it.