I think Kriston or Grinity said last year that the kids will tell you what they are ready for. If they enjoy it and do it, then its right.
Mr W goes through plateaus of skills and likes. We expose him to stuff and let him tell us what he wants to do. He may spend an hour one day then not go pick up the laptop for a week.
Completely agree with your assessment and find this to be true with our DD. She will focus on numbers for a while and everything is about numbers and than a plateau or shift of attention to reading.
And for the does it matter if your child learns their abcs before age 2 question ... I don't think so. I still see that as pushing somewhat. And only if the child really shows no interest in it but it becomes the focus of the parents. By having things available to them and they gravitate to it, I don't see that as pushing but just exposure. DD found some abc books when she was around 6 months and the books had been out because a friend's toddler had been over and was restless so I pulled them out for him. I never thought lets see if DD can learn her letters ... that would be nuts! But she gravitated to them and asked repeatedly 'what's this?' and 'what's that?'. By nine months she knew all her letters. Basically I'm saying sometimes these kids just shock you and instead of worrying if they are in the right age to know it, you might just need to go with their interests and not worry about it.