Worth rebuilding "The Advent" speakers?

I have a double pair of "The Advent" speakers which I purchased in 1970. I recently replaced my old audio system completely. The new system will drive up to 11 speakers. I only have seven connected at the moment. I opened the Advents to see if I might use them and found all the woofer cones shot and I know at least one of the tweeters is blown. Who knows what condition the crossovers are in!? So ---- should I rebuild them? If so, are there modern speakers for replacement that might not deteriorate like the originals? Thanks for reading. -- Dave_in_Ky