I might qualify as a grendel "fan boi" per some of the comments here ... though for me ... like everything else ... there are trade-offs ... pros and cons ...
I got my 6.5G(18) in Dec 2015, so I've had it for 3 years ... for the first year, it had a Zeus Pro 100mm 4x 640(60) on top and got used strickly for hunting, hogs and yotes.
Then, I switched it to target shooting role for 2017 ...
Though I also used it off the tripod for coon, yotes and opossum around the coop and cattle ...
==
And this year 2018, strickly target shooting ..
==
I think of this 6.5G(18) as a "308 on a small frame" ... since the external ballistics matches my buddies .308WIN stoner when he is shooting 168gr and I am shooting 123gr. The main downside to me is the lack of breadth and depth of the factory ammo supply. I wanted to switch to FGM 130gr, and I've accumulated 4 cases (800 rds) but cannot find it anywhere now ... so I'm back to shooting the ELD-M only ... yes I have the 123 SST for hogs, but don't use that for anything else.
So, while I don't think the grendel is "dead" ... it might be one day if the Army adopts a new cartridge and we can buy guns and ammo in that new cartridge ... which I think would be a good thing. In the mean time, I will continue on with the 6.5G(18) ...
Oh, I did break a bolt after almost exactly 2 years ... and about 800 rds. But hindsight indicates I was over gassed (all shots suppressed) ... now that is fixed, I expect the next bolt to last longer.