When you say the statement below, you were basically rebuilding Log Shipping every weekend.

Backup;

Copy and Restore on Secondary;

Start applying Logs on Secondary.

When you have a very large database, rebuilding Log Shipping on a regular basis isn't do-able--especially when you don't have a large window to do it in. One time I can remember that it took about 5 hours just to copy a set of 6 backup files between servers....