I know that. And I already said that I know it. The difference is, they just dropped this guy into the spot of spiderman and will give an origins story LATER. I haven't read all of the Ultimate Fallout series but I don't recall him being anywhere in it so far.
They're going to alienate more readers with this move than they will get in expanded reader bases. I can see it working if spiderman only had about 10-15 years under his belt, but we're talking about a character that has been established as such since the 60's. Spiderman, as it stanRAB now, already appeals to a massive audience.
If they wanted to do this right by their current fans who have their attachments to peter parker spider man and not this new Miles character, they would have included him in earlier episodes so tht when he shows up as spiderman, it make sense.