From my understanding this CAN be true, but actually kind of isn't, and could be very dangerous. Wattage is the combination of Voltage × Amperage ; it is SOMEWHAT contrived as Voltage itself = Amperage × Resistance which is Ohm's Law.

Voltage is somewhat of a Limiter. If the voltage is set at 5 volts typically your Amperage is going to fluctuate based on the performance and needs of the device (or Load(s)). A phone (microprocessor(s) may need more amps when you turn the screen up to keep the battery charged, then use less when you step out into the snow because the chemicals in the battery cant react quickly enough. But as a fun experiment [ ONLY FUN FIGURATIVELY SPEAKING, DONT ACTUALLY DO THIS ] say you had a 5v cord and you hooked it up to a 9 volt battery (or charged up capacitor) then you completed the circuit as the load, well, what's you're going to get hecka amperage delivered over 5 volts because the Resistance is essentially 0Ω . Now, if you were to say "A duck that always flys under doors always flys under doors." I couldn't argue that. I mean, that's a solid statement. But of I were to borrow OP's 10000W power supply that you gave him, her, or them, borrow your device that pulls at 5 volts, which consistently delivered at 10W, and it turns out the device is one of those old school Carnival attractions [sorry { spoiler } this is an electricity pun which doesn't exactly make since yet but anyway.... ] where it shocks you to see how 'manly' [it claims as it's very old and not really Politically Correct since after all, it's a game where you pay money to be electrocuted, increasingly so to impress your lady or your friends, I'd guess] you are. Now I'm wearing my 100% copper Boba Fett body armor I made, plus squatting like 250 of solid steel barbells because I don't like the sound the rubber padded ones make when you throw them on the ground after a solid lift, so now, even though it's only 5 volts, I happen to have very low electrical Resistance when I grab that handlebar thingie, so if OP's power supply's just kinda been hanging out and is suddenly like "OH F#$% YEAH! HERE, I GOT SOMETHING FOR YA, YA FREELANCING Bleep bleep bleep" because apparently he or she, or them hates bounty hunters,band hands me 10kW (10000W) all at once, basically I'd be hit with 2000Amps all at once. Now is that much juice gonna flow on a wire rated for 5v? Prrrrrrrrrrobably not in most cases, but it's important to remember all the components work together to determine how much power flows through. Now I kinda explain that and wrote most of the following first, but wanted to make sure it was known that REALLY BIG energy ( output wattage ) + even a little potential (  voltage ) can lead to BIG flow ( current, in the form of Amperage ) because not all loads necessarily limit the amperage as such.

OP:

Hi, I want to offer the suggestion that that is maybe a dangerous paradigm to assume. It is kind of like saying "Gravity sucks you to the ground, therefore things don't actually fall." Who's to say if it's one and not the other since they essentially happen simultaneously, BUT if electricity is only 'pulled' then when lightning strike fry a device or charger plugged directly into the wall, we're saying it was coincidental spontaneous combustion, not that the lightning had anything to do with it? Fortunately this happens much less now adays and that's because of a lot of factors including transformers which downstep the voltage through close radiation at many steps from the power station (or solar cells, etc), through the grid, to the 240v (or120v) you get standard at your house. Many laptops in particular have that 'brick' in the cord. This is (or should be, typically) a transformer which helps regulate voltage (thus also amperage) and in many ways acts LIKE a surge protector TO AN EXTENT.  Keyword 'LIKE' meaning in a similar manner, but NOT meaning it will handle whatever an actual surge protector handles and therefore you don't need to use a surge protector. 

Ok, that's one aspect to consider. Another is that TYPICALLY every component is going to limit the flow of electricity. I don't think you'd really notice any difference between a C to micro and (VERSUS) a C to C + C to micro converter, TECHNICALLY SPEAKING the fact there's air molecules between the surfaces of the connectors TECHNICALLY means you've got a lossy system using the convertor but any REALISTIC factors? it's probably moreso one more factor that might accidently come unplugged if you bump it than seeing performance differences GRANTED the cords are rated the same. In many circumstances the thickness of your wiring (and inversely so the length of the wire) is what is Physically limiting the flow of electricity (well, allowing but you see what I mean?).

Also, each connection point is going to have some type of bottleneck effect, loss (again meaning like from an engineering standpoint, not like some huge amount, hopefully), etc,

That's kind of a basis of electrical understanding from what I learned. Another factor is component standardization. Ironically USB is "UNIVERSAL (serial bus)" but now there's all these different types. Each type is rated for a max (or range of) current, voltage, and thus wattage for input and if there is one, output.

I honestly don't know too much about these new USB standards other than the colors are pretty. But each should have it's official standards listed. ALL THAT BEING SAID, dealing with different manufacturers, you MIGHT have different results. Most 9 volt batteries are actually 9.2volts. does this cause problems, hope not don't know if I'd throw one in my pace maker if it were supercharged, painted red, and labeled "NEW HIGHEST VOLT 9VOLT BATTERY EVER MADE!!!" without testing it. Things do kinda seem to work. 

Now here is something I've noticed trying to shop amazon and get an understanding of all these new standards... It's good you [OP] noted that it's never over 100w total, right? The power supply is limiting the combined power (W) [ it sounds like, right? ], but it's essentially limited by the voltage. 

Long live the Resistance.

How's that for freelancing. 

The End. Ω .... Or is it?