Or, instead of looking at it as moving all the characters back in time, you can look at it as moving the date of the construction of the Enterprise forward in time and just chalk it up to the butterfly effect, and deduce that Pike did his voyages (including the one to Talos IV) at the same time as the original, but in a different ship. Heck, if you want to get REALLY technical, you could even say that the destruction of Kirk’s dad’s ship was responsible for messing up Starfleet’s ship-building schedule.
And, IIRC, Chekov was 24/25 in the original series, and 17 in the movie, so that gave a 7-year age gap that would also seem about right for the rest of the characters (Kirk was in his early to mid 30’s in the series, mid to late 20’s in the movie, everyone else looked about right in relation to each other).
Exactly. The entire timeline changed the moment Nero emerged and destroyed the Kelvin. It also gave a firm age for Kirk - the appearance of NEro and the destruction of the Kelvin were all stated to have happened 25 years ago - making J.T. Kirk 24 or 25.
It is also possible many of Pike’s voyages never happen in this timeline - it is obvious the whole Enterprise timeline has been moved forward 5-6 years. Those may the years Pike would have visited Talos IV etc — and would account for those voyages being in Kirk’s star fleet Academy at that time.
The clinging to the old timeline is silly, everything changed the moment Nero appeared and George Kirk died - EVERYTHING. Either one likes it and gets over it, or if one doesn’t they can choose to ignore it. I personally love the possibilities they have opened up to change some of the iconic characters and situatons the old Enterprise crew ran into.