That even though they’re in widespread operation today, the aircraft types in question were designed (and certified) many years ago, before ECC was the norm. My impression is that, once their type is certified, new airframes are built to pretty much exactly that specification even all these years later.
Yes, that's my point. Just because new aircraft are designed with improved hardware does not automatically mean the issue is resolved industry wide. Existing equipment will still have issues. So the statement is misleading. Is the number of aircraft with ECC "most" of the equipment in the skies?
[1] Technically EDAC is the correct name of the whole sybsystem, and ECC is the name of the algorithm. But I've only heard it refered as ECC in my industry. I was even initially confused when I read EDAC, so TIL.
That's kind of a misleading statement. Assuming you mean on planes built nowadays, as we clearly see that nowadays planes still flying (6K of them at least) still have issues. We don't need hand wavy comments trying to make it sound like modern day aviation is no longer susceptible, especially when it's in a thread on an article showing how that's just not true