Remington didn't develop it at all. The Special Forces and Army Marksmanship Unit did, and Remington stepped in to help get a SAMMI industry standard accepted for it.
The blueprints they got - they didn't draw them up - had a digital programming glitch on them. The drawings were a translation of what the originators wanted, and somehow the lead and angle weren't correctly shown. Remington has taken the blame for that ever since.
Not really fair, considering they just accepted at face value what was given them.
Why didn't Remington pursue it a lot more at the time? Did they even offer a AR type action? Their focus was on conventional, traditional hunting rifles, and in the early 2000's, the AR was still just a niche tacticool market. Let's not forget, their management had gotten where they were by pretty much ignoring the military market since WWII.
What has been their response since then? The .30AR? Special upper and bolt. Next up, the .300 Whisper, which the suppressor guys they bought, AAC, sold to them. Now it's the .300 Blackout, but it's still just a .30 in a 5.56 case, and that's really been kicking around since before 1984. It's been a niche round for AR shooters trying to make major in Three Gun when AR's were more than frowned on. Once they were allowed, 5.56 has done the job.
Basically, it goes back to management - the focus has been on something .30 cal, and it's likely market research telling them that. The American shooter seems to want it, but really, he's the least knowledgeable to ask, and steeped in tradition, not change. The auto industry made the same mistake, dragging their feet with their product line, all the while the Japanese took the market away.
Remington helped, Remington got slapped down for it, Remington doesn't see the market well, and it's not Remington's type gun or ammo anyway. The 6.8 is all AR right now, they aren't trying to play the Mil/LEO game. Once they old coots get retired, or fired, then the new managers will play, and we'll see some movement.
If they're still in business.