Clean URLs is a concept in Drupal; for example Drupal 7 default URL formatting is
example.com/?q=node/83 though it could be changed just to
example.com/node/83 by activating Clean URLs based on Apache ModRewrite module.
In MediaWiki there is an allegedly identical concept, named "Short URLs"; for example, the default URL may look like
example.com/index.php?title=myPageTitle but can be changed to
What is the main difference between the two concepts and why in Drupal it's so simple to activate and in MediaWiki so complicated? (for example, note the longevity of this MediaWiki guide on this).