Uhm, what are you talking about?
Yeah the Parthenon wasn't rebuilt because what did the Ottomans care? It burnt/blew up because they put an ammo dump in it.
The Greeks have been restoring it, but in the past century they've been mostly occupied fighting those same Ottomans, plus the nazis, and internally the communists, etc..
Once things calmed down enough, essentially in my lifetime, for that restoration to finally become possible--well they're broke. Plus relatively corrupt. It's hard. Also essential decorative elements are in other countries, and as much as the Greeks would really like them back, whelp.
EDIT: to be clear, that pediment will -NEVER- have "reconstructed" sculptures on it unless someone like nukes London and thereby renders the issue moot. The "restoration" will remain deliberately and HIGH-VISIBILITY incomplete of any element that is currently anywhere else. They're not going to undermine their own complaint, and they're going to point every empty alcove to every tourist, whether that tourist originates from an offending nationality or not.
For that matter, it's not even that big by modern building standards, it's just very unique. Dresden Frauenkirche was fully rebuilt from a post-WW2 "Parthenon" condition starting in the 1990s, there's plenty of precedent and technique for projects like this.
The ones they didn't rebuild (e.g. Kaiser Wilhelm etc..), or rebuilt differently(famously Coventry) next to the ruins were left like because by the time it was feasible to do something (i.e. we have all the de-housed re-housed), people thought they were more fitting as memorials.
And plenty of cathedrals were partially rebuilt after blast and fire damage . Cologne is a famouse one. It was wrecked but still standing, much like Notre Dame.
Reconstruction is not a big deal. We built an entire medieval-style Cathedral here in the US just after the turn of the 20th century. They call it the National Cathedral, you can check it out in Washington DC. It is solely maintained from private funds: there's really isn't anything "National" about it in any official legal sense.
I mean, people really want to rebuild Notre Dame. I have no idea why we built the National Cathedral from scratch in the first place.
So this is totally possible, and it's already announced as policy priority of Macron's government and it has numerous extremely wealthy private backers vouching funds.
Why wouldn't it happen?
You have to understand that all of these of buildings are basically being rebuilt perpetually anyway.
The reconstruction maintenance never really stops, and when does because of funding, it probably shouldn't. That aforementioned National Cathedral, barely a hundred years old, needs serious repairs. It's essentially continuous.
Anyway, Notre Dame burnt up almost certainly because they -WERE- rebuilding it already as I just discussed: That scaffolding wasn't left there from the 13th century.
The political and economic landscape of current France is very dicey at best. Pledge =! Commitment. I'm just saying that I wouldn't be too surprised if they end-up would giving up on restoration/repairing for cost and political reasons.
They have hundreds of millions in euros already in the bag from private sources and the fire hadn't even started at this time of day yesterday.
Obviously our common law is not their droit civil
but the generic concept of our promissory estoppel is a fairly universal one. Why wouldn't this happen?
How expensive do you even think this is?
Let's scope a napkin-number: Half a billion.
They can't scrape half a billion together?
Especially when this clearly isn't going to be "done" in a year or two, but more like a decade or two?