I believe the intent is to go into more details from here -- use this as a jumping off point, as it were. It's definitely not a strict dichotomy -- many cards are valuable on both sides, and a number of decks trend more toward the middle than some of his examples.
That said, I think steady and burst econ might be the wrong words. Flurry-friendly and haymaker-friendly are just too cumbersome, and many cards (Sure Gamble, Magnum Opus, Armitage, etc) are both. It's true that the constant build of Kati moves it toward consistency, but the build to a (threat, even) of a massive payout turn can be pretty effective for slamming in with an indexing or series of Keyhole hits.
You can use her to go to $9 repeatedly for Opus-equivalence, or you can sit with her at $21 and dare them to install an Agenda in a server. It all depends on the kind of deck you have and what you're up against.
But, no, the big point of the article I think is less that there's two kinds of econ and two ways in which Runners tend to want their econ, and if you work too much with the wrong one you're going to end up hampering yourself, even with cards that are good in other decks/for other purposes. Knowing how all your cards relate and which ones are synergizing well (across, as Arkhon mentioned as well, breakers working with the right kind of econ in both the playing-down and the run-efficiency stage) is really important. Even among good econ cards, they're not all equal.
This is one of the issues I was having for some time in Anarch -- I was making use of lots of cards that would benefit haymaker style play (siphon, demo run, liberated accounts (which is just a mistake right there), kati jones (with how I was using her), big-turn focus in general), with the fixed-strength breakers that want me to run every chance I get. I switched things out to synergize with the breakers better, and I'm finding myself doing much better because of the change.
I feel like the Runner has definitely has two stages of economy (that they remain in perpetually, so stages might be the wrong term) -- installation and run. Morning Star, against a meta as saturated with Eli, is the right choice from a pure monetary value standpoint, given how quickly you build it up. But with the limits of a 2 MU breaker and the install cost, not every deck can afford it, even if it means more money in the long run. Designing a deck to capitalize on your decisions seems obvious, but I'm all for more talk of how to do it.
(Also, this is my roommate's article, and I know he's working on another to follow it up. The "lay out the basic principles with clear examples that don't cover everything and then go on to do more detail work" is very... him. I know he really wants to talk more about how different decks use Kati Jones, for instance.)