This particular post discusses making music for a client that is not an artist. I believe the difference between receiving placements and creating beats for an artist are fairly similar.
There are generally three tiers of beats which a client or artist chooses from. Your best tracks are placed in the "top tier" of beats, while OK beats are in the medium tier and your lower-end beats are in the bottom tier.
A trained ear can tell a hit beat from a beat that isn't hot. So this is where my presupposition diverges, since Greg Savage discusses writing for a client, and you may not know what that person has in mind. this is because Greg Savage may have a trained ear that he believes would fit in an artistic fashion for a particular show or setting, but the client is -- in essence -- a person who doesn't have that training and may be far less sophisticated in their musical tastes, knowledge, or to be honest... they just want something to "sound like someone else."
For artists, you can charge a much higher amount than the next tier and so forth. The advantage of categorizing your beats into tiers is that you never stop producing and don't have the pressure of making a hit track every time you step in front of your DAW.
In Greg Savage's case it seems that the amount of time you dedicate to a beat, particularly when working for a client -- like a TV producer or what not -- is a crucial form of currency, since you can tweak a beat for 12 hours and not deliver a product the client wants.
In that case, I believe it is wise to focus on quantity, since we're talking placements here. Once you have many beats a client can possibly choose from-- and one stands out, it may be worth it to take some time to tweak it and make it better.
Essentially, Greg Savage seems to be purporting the advertising agency model of creativity, which is fine, since he offering a service -- rather than something that is direct to consumer. In that vein of thinking, it seems advantageous to price out your hours and estimate how many hours you can maintain profitability, versus overhead and other costs, when you're going to create a beat. A lot of it is also based on budget, something I believe Greg can elaborate on in placements.
In any case, I wish you the best of luck. Continue to make a living off music, because very few people have that capability these days.