Incorrect. The average gamer "power games" at least a little. Though they're unlikely to admit it because when certain camps say 'power game' they mean 'munchkin'. Those are two entirely different things.
I dislike the term "power gamer"

I prefer the terms "Optimized, Balanced, Munchkin, and Nerfed"

(but that is my personal choice)
I agree with you in part though most player
power game Optimize to some degree or an other.
Nothing wrong with making sure you are REALLY good at shooting a gun IF you are samurai... or REALLY good at slinging code IF you are a decker...
This is after all the focus of your character! You SHOULD be good at it.
but
power gaming Optimizing crosses over into munchkinism when you push a single focus of the character to the point that you are totally inept at other facets of the game. I am not saying every character has to be great in all aspects, but they should be at least competent.
It the same with real life. (going to use my profession here, so I am going to lose some of you in the train of examples...)
For me, I am REALLY good at big picture thinking when it comes to the installation of control and monitoring devices. I know just from what the total process is, what sensor need to go where, how far apart they have to be for total coverage, I know where the regulators and boosters have to be placed to maintain a strong pneumatic signal and I know where the transmitters have to be installed to optimize cable and tube structure.
However, I am only "fair" at tube bending, and only "good" at wiring.... I "suck" at welding (even though I have my ticket...) so I choose to do welding only when there is no one better then me around. However, I an awesome man-lift operator.
If we put this into game terms:
Process control & installation: 5
Tube bending: 3
Wiring: 4
Welding: 2
Man-lift operation: 6
(and for that, I get paid very large sums of money)
So that is my core skill set as an Industrial Instrument Mechanic and Electrician. However that is not the end al of my skills....
I have received Basic small arms training, (weapons skills: pistols and automatics)
I have to deal with both employees, Supervisors, Clients and suppliers (Etequette, Negotiation, bribery)
I have received medical training (first aid)
I have received basic survival training for extreme elements (survival, specialized in Hot and Cold weather)
I understand the Electrical Code for 3 countries (law specialized into Code rules)
And that really is the tip of the iceburg.
Your character is more then just his Gun... or his spell, or his deck. You are a professional... and should have the attributes and skills to reflect that. No other group of professionals is going to work with a crippled idiot who drools until it's time to shoot something simply cause he is a liability to THEIR survival!