Ever see that thing where one guy drops a dollar bill, the other guy tries to catch it, but it goes by too quickly? It takes the brain time to evaluate scenario, devise a reply, and send the instructional signal to the appropriate muscles...then get them out idle, and into meaningful action.
One of my big kvetches about the push techs is the action-faster-than-reaction thing. Sure...train the heck out of them for a spell, and you'll intercept the attack. However, if we are going to aim our kenpo instruction at aiding most of the people to respond effectively to sudden violence most of the time, we have to operate under a couple assumptions. Some of the most important for pushes are that 1) it will most likely come as a surprise; 2) it will be quick; 3) the environment will likely be pre-hostile to the aggressive action, causing an adrenal dump in you, the defender/counter-attacker.
Surviving the push is easy, particularly if you have ever skateboarded in your life. Backpedal steps, riding the momentum, until you come to a stop. Now what?
If your adrenal glands are firing, you could have one of two likely responses: 1) you're faster and more dialed, and so time the executions for interception perfectly. This comes with spending lots of time in that adrenaline rush state, and learning to move while you're brains on fire and your hands are shaking. More likely is 2) although your perceptive mind works more quickly, and you see the push coming, decided, authoritative responses fom the limbs are...um...slow. Time stands still, but so do your feet, hands, etc. Meaning, ultimately, that if some big angry guy is dead set on pushing you, you're probably going to get pushed. So what? It's a short, quick ride backwards. Keep your feet under you, land firmly when the momentum stops, settle into a combat-ready internal posture with external body correlates, and be ready for the follow-up assault.
As for Carols observation that the techs may have been modified to make them easier to teach, don't discount the idea too quickly. In commercial models, students come and go; the only constant at the studio is the instructor and the lease payment. Looking into "what-if's", any push can also be turned immediately into a grab. That grab can be static, or used to sling your now-misalinged (from the push) butt around like a rag doll. As a student of defense, you need to know what you're going to do to re-establish a functional base after Big Bubba has started slinging you. Commercially, while monitoring liability, there is little you can do to teach little Johnny and his mom what to do in the face of such overwhelming aggression and sudden violence. Enter the benefits of a testosterone-laden backyard school, or a committed instructor looking to pass on quality, and not just meet overhead.
Surviving the Initial Attack (SIA) is an SL4 concept that I (in my own pea little brain) think of as a small technique within the technique that you do before you do the technique. One reason they are hard to write, is they are content rich in a short time (like, 10 things in half a second). Easier than describing the SIA "prefixes" to each of the push techniques, it's easier to say, simply, survive the push. It ain't gonna kill you. What comes NEXT might, so be sure to get your game on fast, and not be psychologically overwhelmed by the suddenness of the assault.
Take Parting Wings...as a non-SL4 (meaning this ain't what Doc sez to do, but it'll give you an idea) survival, count on being propelled backwards with a shove that makes contact. So, before you start whipping your hands in the air like a kenpo spasmodic, take a couple of small cheat steps backwards to give yourself room, and mess with his head a bit about distancing (depth deception). Find a zone of sanctuary, of sorts, out of his reach. Then, as he closes in, you're settled, he's not, and your banging away on him is apt to have better effect. Different than just "step back into a neutral bow".
I've bounced some big dogs...if they push you, your feet are uprooting right out of the NB, and towards the space behind you. Also, by trotting backwards a couple steps, if he HAS turned the push contact into a shirtful of grab, you'll do better at yanking him off his base, making him more vulnerable to a counter, and making it harder for him to establish a base from which to sling you around.
As written, any of the push techs CAN work. But will they? Depends on a lot of things, and if you litmus test them with serious aggression in the attack (front, mouth off, swing a slap at the face, then drive hard with a push as the attacker/uke, and see just how well the defender in the technique line really responds), you'll find most need tweaking -- even at the training level -- to be applicable in the mysterious "street".
2 cents that won't help the national debt,
Dave