I realize your photo is tongue in cheek, but it's not that far from the truth. Go look up the small house movement, where people live in tiny homes as small as 200 square feet. They are truly independent.
Practicing Frugality so as to maximize savings is key. They saved money can then be used for investment.
Saving money and keeping it from getting 'unnecessarily spent' is essential. Generally we give too much emphasis on return on investment. But saving money and keeping it locked is more important.
If locked money can multiply faster, its an added advantage. My 2 personal favorites are (1) dividend yielding mutual funds or REIT (2) real estate. These investments ensures both long term capital appreciation and short term income.
I think you're right, although I guess it depends on your income. Sir John Templeton, who became famous as an investor and of course was a millionaire many times over, was known to put away 50% of his income for a large part of his life.
A happy, fulfilling, and successful marriage is supposed to be lifetime where the couple grow together in loving, understanding and caring for each other. Likewise, ideally, they learn from each other and reciprocate...