It’s probably not because Remington came out with it or we wouldn’t have the .223 Remington, for example.
Without implying Remington has done well in marketing their new cartridges, and without intending to say anything positive about their recent or current business operations, the popular whipping Remington takes online is much more internet hype than reality.
Rem has commercialized some of the highest selling cartridges in US history, and dozens of others which do not share the same “missed marks” as the 30 RAR or the 244 Rem. The 7mm Rem Mag, 25-06, 7-08, 22-250, 257 Roberts, 416 Rem mag, 280Rem, 260rem, 6BR… Remington birthed a great number of highly successful, mainstream, mainstay cartridges in use today. The 6.8 SPC gets flak these days as a “failure,” even though it remains one of the most popular cartridges and parent cartridge for the MSR market - a far cry from any objective definition of “failure.” Gotta remember also - the 300 Blackout was commercialized by AAC WHILE AAC WAS OWNED BY REMINGTON! The RUM’s have enjoyed as much popularity among western and long range hunters which can be enjoyed by any cartridge, and the RSAUM’s demonstrably have done better in their niche market than their predecessors, the WSM’s - both of which enjoy popularity within their market. The 17 Rem and 221 Fireball have sustained as popular colony varminting cartridges. The 222 rem is famed still for its “inherent accuracy” and earned a retained cult like following. And of course, the 223 Rem stands tall as the second most sold centerfire rifle cartridge in the world, and most sold in the US…
Sure, we can point to a few flops like the 30 RAR and 244, but we can equally point to failed cartridges from a great number of companies - even companies with exceptionally high hit rates for cartridge success in market. Consider Ruger - they have a remarkably high batting average with their cartridge launches, but the 300 RCM was at best, a foul tip, if not a legitimate strike out… 32 Win Special, 307 Win - failures to launch, and hell, I’ll even cast shade here on the WSSM’s, as they simply never got the footing they likely enjoyed, and truly languished, despite the relatively higher success of the WSM’s.
But for the 30RAR, the market just isn’t there. Hunters are a dying breed, we’ve all realized 30cals which aren’t easily held sub-Sonic need high BC’s and large case capacities to be interesting for those still hunting, the Mil-Spec Monkey Mafia doesn’t like proprietary AR-15 components, and ultralight and G2 LFAR/AR-10 components have decreased the penalty of building large frames instead of 15’s… It’s certainly a neat little rifle and cartridge.
I’d be interested to look at a 30 RAR in a true, lightweight, mini length bolt action with a 12-13” barrel, suppressed - might make a dandy little hog rifle.