I think what everyone forgets here is that even in retirement, that initial nest egg of $2.5M will continue to grow. The idea is withdrawing 3-4% and living off of it and letting the rest of the market growth compound on itself.
Assuming OP retires at age 40 with 2.5m and withdraws 4% which comes out to 100k to spend during his first year, a statistical projection of his finances will look something like this.
View attachment 359410
Meaning that by age 50 (10 years into retirement) - his NW will be between $2-8 million, withdrawing $96-372k annually
By age 60 (20 years into retirement) - NW between $3-22 million, withdrawing $138-951k annually
By age 70 (30 years into retirement) - NW between $5-53 million, withdrawing $207k-2.2M annually
Not a bad life considering OP hasn't worked a single day past age 40.
The true question OP should be asking is which charities/foundations he wants to leave his money to.