I know your feeling. After reading Alistair Cockburn's books from early 2000 he wrote that many teams worked agile before agile was invented. I had to write to him to ask if it didn't disturb him to see the same ideas but under different names reappearing all the time. His answer was "the half life of a book is 2 years, the vanishing horizon for reading about previous ideas is 5 years".

If you wish to be a cynic you could say that every 5 years you can take a great idea and repackage it under a new name ;)

Still, the good thing is that good ideas don't die! They stick around (in various names).