Why is there no object create date is the catalogs?

Can anyone tell me why there is no "relcreated" column in pg_class to track the creation date of an object?

It seems to me it would make sense to have one as it would facilitate auditing of when objects are created. In addition, it would also facilitate the dropping of objects that have exceeded a certain age.

EG: SELECT 'DELETE TABLE ' || relname || ';'
      FROM pg_class
     WHERE relkind = 'r'
       AND relcreated > current_timestamp - INTERVAL ' 1 year';

Adding that column should be relatively easy and would not break backwards compatiblity with previous versions.
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