This makes some sense. You could even have several fame bonuses based on who built the wonder-type first, who built the "biggest" one, and they can be destroyed but give you fame over time, so keeping them alive longer would benefit you.

We could assume that all Wonders would eventually turn into Tourist Attractions or possibly Focuses for Loyalty to the Culture, as the Parthenon was built as a Temple but is now the cultural Symbol of Greece, the Pyramids were built as Tombs but are now the iconic Symbol of Egypt. Even in disrepair, they remain potent Cultural Icons.

Fame could be a useful mechanism for keeping the Las Vegas-like Multiple Wonder City out of the game. Say, your Religion gives you an Impulse to build Large Tombs Full of Grave Goods. That could be, depending on the raw materials available, a stone Pyramid, a mud-brick Maastaba, an earthen mound, 'barrow' or Kurgan. BUT you would only get Fame Points for building one type of Large Tomb Full of Grave Goods. Build a Kurgan, and even if you later acquire the stone and labor force to build a stone Pyramid, it won't give you any 'points'

There could be 'conversion' points though. Build a stone Pyramid, put a Temple on top, and you have converted the Large Tomb into a Religious Focus, which is a new 'type' of Wonder. Build a Kurgan, and centuries later use the mound as a base for a monumental statue, and, again, new Fame Points for a new type of Wonder.

Yeah, This modular wonder construction is, in my opinion, a great idea, and if the dev team considers to give it a go it would certainly revolutionise the genre of Historical 4X games.

That's just my opinion on this topic, of course.