.220 Swift is really where the EtronX failed.
It wasn't about hunters. It was about paper-punchers and varminters.
At the time, the cartridge was coming back, and Remington
thought they could get the competition crowd on board, because .220 Swift was making new rounds in the competition circuit with heavy bullets (which, in my own experience is not where the .220 Swift excels...
).
But, of course, they introduced the 'revolutionary' new concept with ammunition that included a 40 gr varmint bullet.
...
...
...
...
...
Yea...
Um...
Dead.
All subsequent attempts with other cartridges were dead in the water.
To be honest...
If the EtronX rifles had been offered by another company (such as Ruger - I
hate Remington), and the ammunition [and primers] were still available, I'd probably own one.
All Remington had to do was corner the correct market for the rifle, in order to let the 'virus' spread to the rest of the shooting world, and they would have had a slow-burner. It would have taken time, but they would have had a successful product.
But, no. They chose a nearly-obsolete cartridge that was coming back in a niche application, aimed the co-dependent rifle at that niche group (competition shooters) while retaining non-conforming mass-market characteristics, and then aimed the ammunition at a
completely different niche group (varmint hunters).
Boom!
Awesomeness.
Hype.
Media.
Gun rags.
Dead.
----
As for the .308 ME, it's still alive and well.
It may not be as popular as some other cartridges, but owners love it, and Hornady won't stop making ammo any time soon. If it's not still around in another 10 years, then it may be a failure. But, so far, so good (in lever-actions ... which was the whole point).
.222 Rem Mag...
Though not a huge success, it is still alive and well today, and was commercially chambered as recently as 2014 by Ruger (possibly more recently by others).
It was never meant to be the next best thing. Leading up to the .22-250, it was simply meant to be another rung in the ladder.
Under current conditions, it may not be a high profile cartridge, but it will stick with us for many more years.
If you look at it in no other way...
You can at least look at the .222 Rem Mag as the parent case to .204 Ruger.
Huge a few years back... but where is .204 Ruger today?...
(No better than .222 Rem Mag, is the answer.)