The refrain is familiar by now: In recent years shale-gas production success overwhelmed demand that was already depressed by the recession, and natural gas prices cratered. Understandably, observers wonder if industry’s rush to shale-oil plays and skill in transferring technology to them will result in a similar comedown for oil prices.

Taking a stand on this debate in a recent report are Bernstein Research analysts, led by senior analyst Bob Brackett, who say the shale-oil flood “may not break the levee.” The analysts note that the bear argument for oil ...