That's mind-boggling. Why would building a cathedral/mosque/temple take longer than a lifetime (or half)?
There's also likely an element of not really wanting it to be done since the construction itself is a big part of the draw of the building for tourism.
When you see it, the timeline starts to make sense.
Even pre-industrial London could crank out enough churches in a dozen years to keep a celebrated architect booked solid. But that’s an exceedingly dense urban era, capable of supporting a large array of skilled labor.
Furthermore cathedrals were often build iteratively - e.g. someone finances a new tower to add to an existing centuries old building.