I get my hackles up at attempts to “allegorize” large passages of the bible away.
A more conservative approach, involving comparing scripture with scripture and using historical and grammatical interpretation, keeps open the possibility if not the probability of the day-age theory, in which the creation days stand for ages or eras. But what God was doing behind the scene of the Genesis account is by definition not shown. We don’t have the knowledge to make presumptions about it. It was a time of the miraculous by any fair measure. “Punctuated equilibrium,” if geological and biological accounts actually show that, begins to look a lot like “this was planned so that production of species would neither generate a visible contingent of defective creatures nor stagnate.” Some say chance, I say wisdom.
I like where you’re going, but keep in mind that the day-age theory has two very large problems. One of them rules it out completely and the other puts a rather large hole in it right at the waterline.
1. The days of Creation Week in Genesis are contrary to current evolutionary theory and, indeed, any explanation that involves only natural processes. We see plants before there’s a Sun, birds before there are land animals, no predators or scavengers in existence and a woman is built from a rib bone and dirt, probably coming into existence days after the man as well. No series of ages involving evolution or a naturalistic cosmology could produce these events in this order as part of an age.
2. The word used for day in Genesis is “yom.” Yom can be used to express a period of time (such as “in the day of the Lord”) but it’s most commonly used to describe a 24 hour day or the time of the day when the Sun is up. In Genesis 1 each day is accompanied by the phrase “And there was evening, and there was morning”—something that makes no sense if the account is supposed to describe an age that lasted millions of years.
The day-age possibility is unworkable.