Many reasons. For one, the name matters. Yes, even such a small matter as the name can make a big difference. Do not underestimate brandnames and the first mover advantage.
There have been many examples of people copying original ideas and yet still failing. Even in the event that the copy had superior backing.
It's been general knowledge that the only way to beat an original idea, is if you have an idea MUCH better than the original. Copying an idea or having a slightly better idea simply doesn't work. As a matter of fact, we've already seen this particular phenomenon with BC. BC is not the only digital currency in existence. There have been others. And from what I've heard, some of them were even slightly better than BC in concept. But most of them still failed, simply because they didn't have the first mover advantage. Only Litecoin managed to put up a fight. Ripple might have a chance as well.
People simply go with the most established brand and simply don't bother with other brands. The reasoning is that there must be a reason why a particular brand must be more popular than the other brand. While this kind of thinking is not really deep reasoning (most people don't do that stuff), there's some element of truth to this assessment. As an example, there have been tablets that rivaled the Ipad in specs and even had some capabilities that the Ipad didn't have. But people who did choose these slightly superior copies found out that the support was shitty as hell. While companies could copy specs and even beef them up, copying the infrastructure and support of the Ipad was an entirely different matter alltogether. The Ipad had a well developed app marketplace (which is the main draw of the Ipad) which copies simply couldn't rival. And the reason the Ipad had such a well developed app space was because of its brandname and the firstmover advantage.
The main reason something like Android was able to compete, was because of the power of the brandname behind it (google) that was backing it.
Now, getting back to this hypothetical Bytecoin, what you guys are saying is that this Bytecoin would be able to suddenly overtake a 4 year advantage, overcome the brandname and first mover barrier and get accepted by the same people that accepted BC, getting magically accepted by people and companies whose normal tendency is to to only go with the established brand and then suddenly have a similar infrastructure as BC, where all markets and exchanges decide to denominate their products in Bitcoins as well as Bytecoins, even though we have already seen other digital currencies crash and burn.
And then we haven't even hit the main problem with this hypothetical scenario. The scenario described above would result that this new currency would have a different exchange value. If you try to force the market to have this Bytecoin be the same value as a BC, it would be neccesary to have the exchanges like mtgox incorporate the Bytecoin on their sites. If the exchanges don't accept this, these Bytecoins will be forced to have its own seperate exchange. As a result, you won't be able to prevent the Bytecoin from having a different exchange value. It will essentially be a different currency to BC, and thus couldn't be regarded as being part of the BC supply.
And trying to sell these Bytecoins through a different means (in an attempt to peg the coin to BC) than through exchanges only works if you have enough people that denominate their products in Bytecoins. To employ such a strategy is not something that can be done through the free market. It would be necessary to force people to denominate their products in Bytecoins. Only nations have that particular power, to force people by decree to denominate their products in their particular fiat currency. That's why nations are able to peg their currency to the dollar, because they have the power to force people to accept the pegged currency.
Last but not least, is the entire idea itself regarding the notion of PURPOSELY trying to add to the BC supply. The entire reason BC got popular to begin with is because markets were FED UP with all the money printing. What you are telling me is that the markets would suddenly turn around and say that they WANT to add to the supply and contradict ALL of their previous actions by accepting BC and suddenly support this Bytecoin. Good luck in trying to convince the market to accept this new hypothetical currency that is essentially based on money printing.