IANAL but I'd assume it is hard to argue that there is a common expectation of profit when purchasing art, even though this is why some people buy art. Furthermore, the profits you would make upon reselling the piece of art are not coming solely from the artist's efforts. The artist got paid for their efforts and your profits are coming from your ability to market the piece and negotiate a better deal. In other words, you have some control over how much profits you gain and the artist is out of the picture (ie. they are no longer spending effort to help you make profit).

But a securities law expert would have a better explanation

It isn't clear how that passes points 2 or 4. Maybe if you explain why you think it does, you'll get a better answer.

I guess something that's important to consider here is that when I wrote this I was considering whether the Ethereum presale in 2014 would be likely to be classified as a "security". I thought theDAO was a pretty terrible project and wanted to illustrate just how broad "investment contract" analysis could be stretched.

So to take your example, should I decide to pre-sell a commission of several pieces of art that I plan on working, the reasonable expectation of profits seems like a reach bc those who buy art do not solely do so to flip it and make a profit. I wonder whether the same could be said for those who invested in Status, Bancor, and Tezos?

Unfortunately, common law tests like "investment contract" analysis are, by design, super ambiguous.