Reminds me of some work i did at the end of my thesis. I was looking into some magnetic field effects in a new material that every one was working on. It felt like i was truly making some new discovery. It was true, except for the fact that similar effects had been extensively studied in the 80s on some similar materials. My material was new, not so much the physics. However, except for people who bothered looking up the old papers, it was like two parallel worlds. In the end, i could go further in my discoveries thanks to those old papers, so it wasn't a waste of time. But i saw new papers coming out unaware of those old works. If not for those new works, those old works from the 80s might have disappeared into oblivion.

Science really is a matter of discovery and rediscovery. The matter of attribution is important, not so much for the science itself which sometimes needs the right person to take care of PR, but from an ethical point of view. Those two can live on two different planes though, for better or worse.