Apache user, poor security. PHP read/write files

I'm building PHP CMS system and read/write files is a problem.

Please write your opinion about this:


Why shared Hosting servers (paid hosting) uses Apache default configuration?
running Apache runs as nouser for every VirtualHost.

Running as different user is more secure, every .htm .php shouldn't have read permissions for "others"
My suggestion is: every user may have 1 account and 1 group (not same name as user),
-username for using in shell and own files, and
-group for give permissions for this group.

Apache may be in every of this groups.

Then a file could have this permissions 770 or 760 , user=username, group=groupname, Apache can access to this file, but not other users can.

It's a really simple to do, only doing some changes in administration software.
Creating a new group,
and putting in httpd.conf :
<VirtualHost *>
...
...
User groupname
</VirtualHost>