Oh I see! Yes, agree with you there OohNoDooEy
A early morning nap certainly encourages an early wake up in the morning. I don't necessarily link that to changing to one nap though.
An 7 month old, for example, waking at 5am then napping 7am-10am and 12-2pm. Then will be knackered by 6pm so want a very early bedtime - that's a baby who needs a later morning nap. That needs some "powering through" to move the whole routine forward by a couple of hours.
Early waking is not directly a sign, on its own, baby is ready to force the issue and not allow a morning nap. That's what I meant. Early waking defo needs a later morning nap. Sometimes it means no morning nap is needed, not always though. Well, not in my experience anyway.
If you want them to wake up after 7am...
My DD was waking 7am (ish, give or take half an hour either way). From 5 months old right through to 18 months she had a 9am-11am nap and a 1-3pm nap. Bedtime 7-8pm.
They are never all the same...