Actors today and yesterday how do they measure up to each other?

What % of actors that are in hit shows today will still be here 10 years from now? And have they finally jinxed the 'stereotype'? Ted Danson of Cheers couldn't buy a job. Neither could Shelley Long. It seems that actors are burning out audiences way faster than 40 years ago. I still watch the old movies. Those were the stars. The ones we have today only think they are because the public painted stars on their back. Will we speak wistfully of Brad Pitt or Angelina, as we do of Spenser Tracy and Kate Hepburn, in 40 yrs.