There is a counterpoint - or perhaps a point of clarification - to be made to your last statement.
Aerobic and anaerobic power tends to be like a teeter-totter for most people. The height of the center pivot is more or less determined by genetics (and perhaps epigenetic factors as well); your training and diet determines to which side the seesaw tips and to what extent. Ultramarathoners tip this almost entirely to the aerobic side; marathoners and triathletes slightly less so. On the other side are guys like powerlifters and NFL linemen. Most gym rats are tilted more towards the anaerobic side simply because that type of power is easier to develop than aerobic power.
Weight lifting tends to build Type II muscle fiber, and the presence of of this "fast twitch" fiber tends to correlate with the production of lactic acid when given tasks that exceed the duration which can be fueled via the phosphogen system (which is about 30 seconds of work for most people). The production of lactic acid is a good thing when tasked with an anaerobic effort (everything from, say, 30 seconds in duration up to perhaps 20-30 minutes for those with substantial pain tolerance); the more lactic acid that can be produced and tolerated, the more anaerobic work that can be performed before a recovery cycle of sub-aerobic threshold work. If you want to win 1500m running races, crush a 2000m row, or drop your buddy in a bike sprint to the next stop sign, this is the mechanism to do so.
But when faced with an aerobic effort of long duration, total output can actually be reduced since that "fast twitch" muscle will produce lactic acid even at a relatively low output level (a rate of work which would be at or below the aerobic threshold for Type I "slow twitch" fiber), which in turn causes most people to slow down because lactate accumulation is uncomfortable, and it also burns up your glycogen stores faster than your gut can refill them. Someone in the 180-200lb range who is accustomed to working at lactic threshold can burn 800 kcal/hr in this mode - with over half of that being glycogen (carb) - but only replenish maybe 250 kcal/hr, and eventually that math catches up when the muscles and liver run out of stored glycogen. Won't happen in an hour-long workout at maximum intensity, but a few hours at an intensity factor of 0.9x might do it, and 6-8 hours at lower intensity factors will also be an ass-kicking. If you'd spent your time building more Type I fiber, you'd burn less glycogen for the same output, and thus could generate the same power output for longer.
Going back to your example, taking the extra time required to develop that last 15 lbs of deadlift and putting it instead into low-level aerobic work might be the better choice for a hiker, hunter, cyclist, etc. I don't know how to quantify that additional training time - is it 15 minutes/week, is it an hour a week, is it five hours a week? Is it causing stress and inflammation that will interfere with other training or one's general health? So I don't know what sort of negative effect it would actually have on one's fitness. But there is an effect, and I suspect it's quantifiable for someone who is paying close attention.
