I think the symptoms of impending driveshaft center bearing failure may have been minimized over the years by members of the community in general. There are lots of posts on the board about people driving the car until there is noticeable vibration on takeoff, loud growling, rumbling, even crunching noises. Generally speaking these are accompanied by comments such as "wear", "needs attention", "starting to go" or "sometime soon" etc. It all comes down to lack of familiarity with bearings. Any bearing that is making any noise is worn and is prone to failure. When the center bearings are just starting to wear they hiss, in my experience. If you drive next to a high curb or a center divider, you can hear the hissing. It sounds like a compressed air leak. THAT, in my opinion, is the time to get that bearing out of there. If it has already progressed to rumbling, then the bearings themselves or the races they run in are already seriously damaged and heat is building as a result. Heat causes the side seals to fail or to fall out. Compromised side seals are prone to moisture ingress--a quicker end to a dying bearing. Dropped side seals will let enough dirt in to destroy what's left of the bearing in days.

I would take your shaft to a competent drive shaft shop or machine shop that does drive shafts. Most of the things it hit are far softer than the shaft, as long as it didn't hit the ground. They will be able to tell you if the shaft needs replacement. If any of the yokes that the u-joints fit into were banged badly, deformed, or if the shaft was bent, then yes, it will be cheaper to buy a used shaft and rebuild that one.

Scary experience!