The real purpose of the scrum in rugby is to tie up half of the players (the forwards - the backs are not in the scrum) when restarting play.

Literally to remove the forwards from the play after a restart, by having them all bound together with their arms twisted around each other.

Then, when the ball pops out, the field of play is nice and empty for a few seconds and some running rugby can take place, while the forwards slowly untangle themselves from the scrum.

To translate to software engineering and agile, if scrum is taking half of the team's developers and tieing them up and preventing them from doing any work, then scrum is working exactly as intended.