There are 75 million Mac users, many of whom have iTunes accounts and credit cards on file – they can buy from the Mac App Store with a single click.

20% of 75 million is 15 million. 15 million copies of any paid app is huge.

Also, let’s not forget that Mac sales has been growing for years, while the PC market as a whole has been shrinking. Today, there are 3 times as many Mac users than 5 years a go.

Also, it would seem that Mac users tend to spend more money on software, than the general PC user. [citation probably needed, but whatevs]

That could only be true if you ignore software for business (even small and medium business, not just "enterprise").

Probably, but there's plenty of good money in selling software to humans.

And games.

Of course.

From my observation that relation has held true since the '80s.

That's about 2% of the total amount of desktops. I don't know the exact numbers, but I assume that it amounts to several dozens of million sales.

Are we getting so disillusioned that we consider to be "such a small potential userbase"?

No, it's just that when you go out the first time you pick the low hanging fruit.

It's great going for low hanging fruit, but you need to be realistic about things as well. Bigger market means more sales, but potentially only at a lower cost. Markets are a funny old beast.

At the same time, every member of that 10% bought a Mac desktop, and therefore bought a product with high margins. If 10% of your potential audience has no problem buying software, especially high-margin software, they'll be easier to sell high-margin software to.

20% is huge. If you have a product so good that 1 in 5 Mac owners will purchase it, don't hold back.

Well, according to this [1] the Mac install base is around 66 million users. So, if 20% of them bought your app for $1 you'd be $13 million dollars richer. That seems worth it to me. It seems that you are underestimating the size of the market and potential the to make money by writing applications for the Mac. You are also ignoring the fact that Macs sell at a premium so those 66 million represent not the bottom end of the market, but those with money to purchase services to make their lives easier.

[1] http://aaplinvestors.net/stats/mac-installed-base/

Those numbers are one year old (WWDC 2012). In the meanwhile, Apple has sold 17 million Macs. Mac install base is closer to 75 million.

A lot of those are going to be replacements for existing Macs, however. (Mac user since original 128k.)

My estimate of 75 million was conservative, it’s closer to 80 million.

Half of all new Macs are sold to people who are ‘new to Mac’[1]. Even the people who buy a replacement for their old Mac will often find other uses for that old Mac or they will sell it or give it away.

One year a go, Mac install base was 66 million. Since then, 17 million Macs have been sold. 8.5 million of those are sold to people who never owned a Mac before. Let’s imagine that all the remaining 8.5 million units are bought by existing Mac users, and that half of them are bought because the old Macs died. That gives us a new total of 78.75 million.

[1] http://www.forbes.com/sites/carminegallo/2012/07/25/7-sure-f...

> So, if 20% of them bought your app for $1 you'd be $13 million dollars richer.

http://sivers.org/1pct

> http://sivers.org/1pct

GP is not an exemplar of the 1% fallacy. GGP asserted that their product would have a 20% install base, so GP used that number.

Small, but moderately affluent userbase, who have a 30ish year history of paying for shareware and software at a far higher rate than windows users.