Even with this strategy, you're not retiring at 45 unless you are frugal, have cheap hobbies, and never have kids or a non-working spouse. Also take care that you don't have any parents, siblings, or extended family that come to rely on you. Also don't forget expect to live anywhere even remotely expensive, unless you like camping.
> non-working spouse
Does that mystical creature still exist? Or is it perhaps more likely if one of the pair has a high yield income?
Not sure why this was downvoted; it doesn't say you shouldn't do all those things, only that they're no guarantee you'll be able to retire at 45.
You're not wrong, a family is more expensive. But if both parents pull the same (or similar) salary, it is enough to still retire at 45. Requires using more tax-advantaged plans to play for college, and may not work well in expensive cities.
Re: cheap hobbies, I used to date a public school teacher. She would save to go on guided trips to Antarctica, Peru, the Galapagos, New Zealand. You can live an amazing life if you plan for it.