My answer to "how much money would make you happy" is infinite. There will always be something I spend money on to make myself happier.
Yes. Getting a private sushi chef will make you happy. But after your 1,000th straight day of having your own personal sushi chef make you meals, it starts to become mundane and no longer provides much of a net positive effect on happiness.
What will significantly effect your happiness long term is negative things happening to you. Not being able to pay your bills, not knowing if you're going to lose your home next month, eating ramen because it's all you could afford - these sorts of things eat at you.
The $75k figure people throw around is the point where, supposedly, you're making enough money that you will avoid most of the stresses/negatives of not having enough money so there's nothing dragging you down from "baseline". Adding more money after that will allow you to make marginal increases in your happiness, but nothing significant relative to removing those negatives.
I don't doubt your sincerity, but it might be worth considering that a common theme in American lifestyle-pursuit fables (i.e., "Brewster's Millions" [1985] or "Blank Check" [1994]) is that the kind of 'happiness' you're describing ends up being rather hollow in the grand scheme of one's life.
I feel kind of sorry for people who feel like they need more and more money to make themselves happier. It seems like a trap set by a society that values consumption too highly.
I think you'd probably be surprised if you had billions of dollars how much less happier you would be than you expect. There is a reason billionaires don't act like they're high on heroin 24/7. Money isn't some magical happiness generator that ramps up with every extra dollar available.
the point of contention with the other responders here is probably one of terminology wherein they are discussing previous literature (which really amounts to "reducing causes of unhappiness" more than "actually increasing happiness") and you are discussing actually increasing happiness beyond the "baseline" discussed in their cited studies.
i'm in agreement with both lines of thinking; after a certain point, money doesn't reduce the major causes of unhappiness much further, but it probably does provide more reasons to be happy, if only transiently. the hedonic set-point is far from a settled concept.
In short, the more money you have, the more politics you have to engage in, and that doesn't always translate to increased happiness for you.
The total NET happiness over a lifetime might be higher with the $150k, because like you said you could retire much earlier. However, happiness is an odd topic, and overwhelmingly people always have a baseline happiness they return to. And the $75k figure is sort of the number that allows you to have that baseline happiness (i.e. no overbearing negatives in your life due to money). So I would think it'd very probable your lifetime happiness would be higher with the $75k job.
Everything in this comment is a generalization and obviously doesn't apply to every single person. Really smart people working at Google don't necessarily fall into the generalizations of numbers like these because on the large scale (billions of people) Google engineers are outliers.