Loaded question.
First, because the teminal growth point in many Yuccas (and all Agave) are transformed into a flowering spike it can mean the death of the flowering rosette (since the growing point has changed into terminal growth of the flower stalk), but not the plant. But, as you point out Yuccas that do 'die' after flowering sucker from the base and the plant lives on. This is true for most Agave as well, with a few exceptions (i.e. species that do not put out root suckers, Agave utahensis ssp. kaibabensis, Agave montant, etc.). Once a clump of Yucca is established it can flower every year with the plant remaining strong and continually sending up new suckers.

Most Western Yucca can flower every year without the main stem dying, or showing any ill effects. Here is a link to a picture of this in Yucca elata (the hardiest of the tall trunking Yuccas, taking -25f here in Ontario, Canada): http://www.delange.org/YuccaSoaptree/YuccaSoaptree.htm

Hope this helps!

Sorry to chime in here.

This year I snapped the flowers off my filamentosa to hopefully start getting a bit of a trunk-like effect as others have mentioned. There were some pictures of some filamentosa that people had done that with so I thought rather than have suckers everywhere.....