From version 1.4, The All Pages in the backend will use ReactJS by default.  And it works well even you have a few thousand pages. 

You will see a similar message when you have more than 1000 pages:

The total page number is 8789, only display 1000 pages here for better performance. 
You can use the search form to find the specific pages or change the system.all_pages.display_limit_numbers setting to display more pages.
Default system.all_pages settings:

    "react_js": 1,  // change to 0 if you want the Laravel blade template instead of React
    "display_limit_numbers": 1000, // By default it will display 1000 pages. You can change it to what ever you want
    "recently_added_numbers": 50, // Only display 50 recently added pages
    "display_option_numbers": 20 // Only dislplay the search option when the total page number is more than 20

Note: The search box of React page only support the search for title, menu_title and the slug