Sure, money is fictitious and meaningless once you've moved into the f-you echelon. By definition. Perhaps for that segment piping it into creative endeavors is fulfilling and worthwhile.
For everyone else for whom money is a meal, rent, or essential good instead of an expletive, who cannot afford to take an ethereally long-term view, this advice is out of touch with reality if not plain dangerous.
You and I read his advice quite differently. Once you quite your job to pursue your dream you have a finite runway determined by your savings and minimum expenses. He is suggesting you use that runway to build you dream instead of using it to try to get funding for a longer runway.
Without your "bad dreams" we wouldn't have the Red Cross, Kiva, Linux (or a majority of *nix releases), GPG (or lots of other OSS projects), One, Doctors Without Borders (or any number of other non-profit organizations), immense amounts of historically important art, music, documentaries, museums...
Some of the best, most important dreams in human history weren't profitable.
One would argue that "social profit" (ie: where society profits) is where all those not-for-profit "bad dreams" go.
The Red Cross movement especially brought forward the Geneva Conventions (which improved the conditions of prisoners of war), successfully fought epidemics, and (in my opinion) began a tradition of humanism that combats extreme fundamentalism in a practical non-violent way (which is why the worst fundamentalists target Red Cross/Red Crescent workers.)
All of those things are profitable in the sense that's relevant to this context. In this context, "profitable" is clearly being used to simply mean financially viable. Nonprofit organizations produce surplus revenue, they just happen to use that surplus to further invest in the official (and legally-approved) goal of the organization.
I agree with you in that I think Jonathan is speaking a bit too idealistically. But I agree with Jonathan in that I personally don't put a lot of 'value' on holding on to money. I would rather spend my (minimal amount of) money enriching others lives, doing small things like tipping well or picking up friends meals. I think ultimately it is up to the individual how they derive their happiness, and ultimately decide what value they assign to monetary wealth. Maybe rather than categorizing money as meaningless, it would be better to describe money as a tool whose utility is determined by its owner. And then the key is that we must avoid judging others when they place a different value on their money than we do.
The point more is about how money isn't actually a thing. It's one of many ways to obtain something. Just one of them. For example if you are a high profile game developer, no matter what you release for a long time you will pay your basic bills, not because you have money now, but because you can get it relatively easily. It's not the money anymore since once you are enough in demand you can essentially print money by working so it really is meaningless in that context. It's very very different from someone who has no money and no real way to obtain it. It's not the money but the ability to get it easily that matters.
For everyone else for whom money is a meal, rent, or essential good instead of an expletive, who cannot afford to take an ethereally long-term view, this advice is out of touch with reality if not plain dangerous.