Significance of Lord Ram breaking Lord Shiva's bow

Pinaka or Shiv dhanush was the bow of the hindu god Shiva.

Vishvakarma crafted two divine bows.He gave Sharanga to lord vishnu and pinaka to lord shiva,who killed the demon tripurasura with it.
The bow was broken by Ayodhya's prince Rama when he attempted to string the bow, during the swayamvara of Sita, thereby winning the princess's hand in marriage.

He didn't break Shiv Dhanush for insulting Shiva, Breaking of Dhanush has following significance.
1)Lakshmi can only be stationary near Vishnu. So Sita can only be of Ram.
2)Shiv Dhanush was broken to break the egos of arrogant Kshatriyas who were also tormenting the people like Rakshasas.
3)Breaking of Dhanush had depicted that ParshuRam's tenure is over and now the earth is in the hand of Shri Ram.
4)Both superpower Shiva and Vishnu are same and there is no any difference in them.
5)Ravan was informed that more powerful person than him has come on this earth because he was also present on that Swayambar and couldn't even move the Dhanush.