I'm not quite following the reasoning here. Are you just saying that in any infinite amount of time we should expect everything conceivable (and inconceivable) to have actually existed?
No not anything conceivable only things that have a chance to exist. For example, a giant solid gold planet can physically exist in this universe but there is no probable process for it to arise. I suppose a super developed alian race could search the galaxy for all it's hold and create one.. But for what purpose?
This is an example of something that can exist but will never exist.
Other things however like intelligence, sentience, can and do exist. The benefit of sentience is that it's remarkably good at reproducing itself therefore selection will favor it. Intelligent sentience should at some point pervade the universe. Looking backwards, it's likely that it already has.
We can us AI as an example. If we ever manage to create AI worlds and universes, we then proove that it can be done. If we make multiples of them ( and we would) then we have a statistic. Let's say that 1% of all intelligent races create 100 ai universes.
Do you see what happens now? 99% of all sentient life and their environments should be a creation of another. There is no reason to assume our universe is the top of the food chain. In all likely hood we are within the 99%. All we have to do is accomplish created AI worlds ( and we are very close), then the odds of us being created jump way up. If you look at quantum mechanics some of the fundamental laws of nature behave very digital like.
In an infinit of existence anything that has a probability of happening will and already did. This would mean highly evolved sentience as well. Its really the only answer to the anthropic principal.