EOS didn't fail, it's a successful blockchain technology on its own, Cardano isn't bad either but going against or Vs with ethereum is night and day, developers will continue to choose ethereum blockchain over Cardano for some reasons, this won't stop Cardano and others from becoming a success
At this particular moment its really hard to tell which one's decisions will lead to better consequences in long term.
Its pretty clear both of those have the ability to create short term hype, but in long term hard and not fun decisions like creating eth2.0 for many years to become something bigger as project.