It's unlikely that a general cure for disease will come about as a result of cracking aging; some of the more outlandish possible solutions (i.e. direct intervention by medical nanotech) might qualify, but those require such advanced technology that it probably doesn't make sense to talk about them in conjunction with conventional Malthusian constraints. In any case, the accident rate isn't that low, and birth rates appear to correlate negatively with lifespan and standard of living; I haven't actually done the math, but the constraints on the problem seem to suggest a steady state well before Malthusian catastrophe, even in the absence of regulation.