I have also ready people saying about pushing morning naps later having an affect on morning wakings. I'll bump the thread to see if any of these posters see the thread.
Personally I don't believe that making morning naps later affects morning wake ups. Morning nap gets later naturally as the baby gets older (and transitions from two to one nap) and this may happen co-currently with morning wake up getting later. But I believe these are two things happening at the same time, rather than one being the cause of the other IYSWIM.
Between 6 and 12 months has been the age that most of my children have established sleeping though consistently without waking up. This process of learning to sleep through usually begins with an early wake up because baby can perhaps go 9 or 10 hours from bedtime and need a re-settle, but is not yet at the 11-12 hours per night it will eventually settle at.
This nearly but not yet sleeping though phase is what I would consider the cause of early mornings.
As we approach 12 months old (or thereabouts), in my experience, baby naturally starts to be difficult to settle at the usual 9.00/9.30am nap time an starts staying up later in the morning. Eventually the morning nap gets so late that it merges with the afternoon nap to become a single lunchtime nap.
This transition of two naps to one is the cause of morning nap getting later IMO.
Moving to 1 nap happens at a similar time to fully establishing 12 hour nights, but is not actually a cause and effect thing as is suggested by those who recommend deliberately making morning nap later as a solution to early wakings. IMO.