It does. Which is why I think the most common Pokemon would be the most powerful if there’s no maximum trainer level, because you can just keep pumping it up. Rare Pokemon are hard to pump up because you can’t get the candy.
I guess it might be worth listing the CP increase per level to try to work out what’s the most powerful.
That being said, chatting to @gruzihr the other day, he pointed out that the same Pokemon can have different types of attacks that do different amounts of damage. So you’d have to consider this when trying to work out what’s the most powerful Pokemon.