Joe Quesada after he stepped down as EIC became Chief Creative Officer, per wikipedia, tasked to "ensure that all portrayals of Marvel's characters and stories remain true to the essence of Marvel history." In the case of the cartoons, he was producer on the USM trash, and the current Marvel's Spider-Man cartoon. In the Marvel's Spider-Man cartoon, Quesada voices a character of an avuncular coffee-shop owner...which is the first time any editor other than Stan Lee has promoted himself that way. So yeah, Quesada does airs of wanting to promote himself as a brand alongside Spider-Man and he does have and has exercised a say on Spider-Man.
The ideology of a young Spider-Man was launched by Bill Jemas former President of Marvel (and commissioner and co-plotter of the first arc of Ultimate Spider-Man). Jemas and then Quesada have obviously promoted people at different parts of Marvel and whenever producers and others have talks with Marvel their say and opinion is going to reach the ears of creators like movie producers, game producers and so on, rather than fans like us. That's how power works. Quesada is a successful EIC, which is not to say of course that he's a good EIC (I rank him as mediocre on the whole). One can be successful without being good at one's job...so that gives him a sense of seniority and so on. And from what I've read on a personal level, he's pretty affable on the whole, so it can be hard to challenge his ideas or oppose him outright.
Historically Marvel EICs get fired or crash and burn somehow, that happened to every editor aside from Stan Lee until Quesada. That brought a lot of instability to Marvel in some respects but it also meant that there wasn't any central figure to enforce a common ideology or viewpoint, a single perspective that defined what Marvel Comics should be and so on. Quesada though got promoted and the result of that is that EIC after Quesada don't have any real power or say. It's a fairly neuteured position, for better and for worse. And obviously thanks to Quesada's promotion, interns and other assistants get ahead by agreeing with him or enforcing his views. By that I am not saying Quesada practises cronyism that's just how corporate structures work. If you come there and you want to get ahead you agree with the boss without him asking, before him asking.
Fundamentally, outside media doesn't matter zilch. Ultimately the movies, the cartoons, the games, the comics...none of them matters in terms of the stuff that truly generates buckets of cash for Spider-Man, and does the actual job of introducing Spider-Man to new audiences.So what is the point in the mandate if they two are so far apart anyway?
Remember the real introduction for Spider-Man is merchandise. Toys, pajamas, stickers, stationery, bedspreads and so on. Every day new babies are born. And each baby's parents are gonna decorate the cribs with Spider-Man logos, Spider-Man stuff here and there. These little tots when they are 1 years or 2 years old will know and recognize Spider-Man's costume and logo long before they can speak and understand...everyone knows Spider-Man long before they find out he's Peter Parker or what age the character is.
The age of the character is fundamentally irrelevant to the appeal of Spider-Man. In terms of comics...the highest period of sales was the era of the marriage from Michelinie-MacFarlane all the way to Maximum Carnage. Sales dipped when they tried to get rid of the marriage during the Clone Saga (and before everyone talks about how successful the early issues were, the important thing is that sales dropped when they said Ben was the real deal, and the Peter who readers thought was Peter for 20 years, i.e. the one who got married, was the clone).
The fact is in terms of eyeballs, none of BND and Slott's run will match that period, and they will never catch up.