The original builder felt strongly enough about the oak beams to plant replacements. The restorers, or whoever hired them, did not. Perhaps they knew that 500

The original builder felt strongly enough about the oak beams to plant replacements. The restorers, or whoever hired them, did not. Perhaps they knew that 500 years in the future there would be better alternatives and were not as locked into the original design as the first builder was. Not all such decisions are short-sighted. Edit: I think it's been shown elsewhere that it is not the date that you launch the next probe that is important, but the speed at which it travels.