Moving everything from root to a subfolder

edit config.php

$config['base_url'] = 'https://example.com/prelauncer/';

I went to application/config/config.php and changed this line:

Code:

$config['base_url']  = get_domain();

into

Code:

$config['base_url']  = "https://example.com/prelauncher/";

[I mean, the real domain] yet nothing seems to change, even when trying on different browsers and cleaning the cache.

Also, I noticed that, along with other folders and files inside /prelauncher/ (application, assets, database, system, uploads, index.php,...)
there is a .htaccess file.
There, I tried and change this:

Code:

 ...
  # If your page resides at
  #  http://www.example.com/mypage/test1
  # then use
  # RewriteBase /mypage/test1/
  RewriteBase /
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteRule ^(.*)$ index.php?/$1 [L]
 ...

into this:

Code:

 ...
  # If your page resides at
  #  http://www.example.com/mypage/test1
  # then use
  # RewriteBase /mypage/test1/
  RewriteBase /prelauncher/
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteRule ^(.*)$ index.php?/$1 [L]
 ...

but again nothing changes...

It seems that I am stucked.

Now I will try ivantcholakov's suggestion, although I definitely believe there the solution should be the first one...
Where am I wrong, please?

remove trailing slash
in your .htaccess
RewriteBase /prelauncher