imo, there's nothing that wrong about the glass shafts i used to use, way back when - micro-flite and gordon. if micro-flites were available today at a price point equal to, or less, than beman ics carbons, i'd definitely be in queue to buy a few dozen for my heavier draw weight bows.
for whatever reasons as to why they were all terminated, it's a moot point at this date and time. it would probably be a risky marketing venture to tool up for glass shafts today, and even with mass production the retail cost would be at least equal to carbon shafting.
if glass shafting does emerge on the market, i think carbon will still outsell glass because, imo, carbon shafts will always be lighter than glass shafts (comparing spine) and that allows a huge latitude range of front end weights for really high foc arrows.
ymmv.