It is the nature of floral media. When you go to a movie or to the theater, your viewing experience only lasts a few hours. I think not. The experience of a concert, a short song, a meal or even a drink with a friend certainly is short lived, yet is still quite enjoyable. The newspaper or magazine is usually savored for only a few hours and then discarded.
Flowers do some pretty remarkable things.
They make people happy. They bring a nice atmosphere to settings. They help make occasions and events seem extra special. As long as they fulfill that function for that event or occasion they are doing what they should do. Don't be sad if they don't last on and on.