Yes and no. By itself, the slow and arduous of social democracy merely mimes the fate of Tanatalus: each t ime you reach the top of the hill, the stone rolls back down.
Whatever we achieve, we achieve in a period of three to 7 years, after which (barring revolution) comes a long period of slow decline, with only part of the gains being preserved. Whether we know it or not, 'our' task during those years (often longer than a generation) is merely (at best) to reproduce ourselves as a new generatio of cadre to be on hand for the next explosion. (Bertell Ollman makes this quite clear in the last chapter of his _Dialectical Investigations_.)
Those who, in a perid like 1935-39 or 1963-68 persevere in the "slow and arduous" become one of the bitter jokes of history. In such periods one must aim for everything; being "reasonable" is fatal. After the period ends, we return to your slow and arduous (which is, really, a pretty flat line, not a rising line).
Carrol