This has been a reoccurring issue in WordPress. See these old trac links that are 9, 7 and 6 years-old respectively: https://core.trac.wordpress.org/ticket/3614, https://core.trac.wordpress.org/ticket/5303, https://core.trac.wordpress.org/ticket/14579
The challenge is that WordPress was built primarily for chronological posts since it began as a blogging tool. Page management was always secondary. WordPress still lacks an elegant solution for large-scale (>100) page management/content management when working with large amounts of non-chronological/hierarchical content like pages. The current list-based screens require paging through lists of data and make it difficult to see the hierarchy of content when the amount of content exceeds the upper limit of the page size (which defaults 20, max of 999). Other content management systems like Drupal and Umbraco use a content tree-based approach which makes managing large amounts of hierarchical content easier from a user experience perspective.
Until this limitation is addressed in the core WordPress admin area, you'll need to resort to outside solutions/plugins.
This best plugin I've found to manage a large number of pages is this one: https://wordpress.org/plugins/cms-tree-page-view/. It provides an ajax-driven, hierarchical tree view menu under the Pages menu in the WordPress admin area that provides a much better user experience and performance when working with a large number of pages (>100). There are other plugins as well, but this is one has 90,000+ active installs, an average rating of 4.9 starts with over 250 total ratings and is being actively maintained. It loads the top-level pages first and only loads child pages/content when you click to expand a node. It can be used with the pages post type or other hierarchical custom post types.
I have a site where we have nearly twenty thousand pages (with a lot of hierarchy) and this is the only way to deal with them. The built-in Pages menu is useless and often doesn't even load when you get a high number of pages like that.
Update 26/09/18: the CMS Tree Page View plugin is no longer supported and has only been tested up to version 4.8.7 of WordPress