They can afford to stop. It’s very much true that the defense base and spending is propping up a flagging manufacturing segment. But, the plan on the books already is to reconstitute their military to be able to seriously threaten a NATO neighbor within five years. They are in a miserable position with labor shortages and returning men to the economy is badly needed (even that won’t reduce dependency on Central Asian migrant flows). And they have a host of nations itching to more openly and greedily return to Russian petrochemicals the minute they can do so without fear of sanctions.
Russia doesn’t need the war to adopt a defense production/war footing economy. They can do that without the war, and they will. They are not at all sensitive to consumer preferences, there’s not going to be any pressure on the apparatus to shift focus. The (admittedly capable) technocrats who manage the economy and finances would very much prefer to get away from the current model, and are working miracles as is.