MaximRecoil
Sorry, but the more I think about your rebuttal, the funnier it gets, so I can't resist a couple more points--
I said there is no such thing as a 500 pound bicycle, not "no one can move a cargo bike laden to 500 pounds". I stand by that--go ahead and show us a bicycle that, by itself unladen, weighs 500 pounds. That's a double-dog dare. If the bike starts at 500 pounds unladen, then putting a plausible rider of it on top of it already increases the gross vehicle weight to close to 700 pounds. I'm sure there's probably someone who might do this as a stunt, but so what? This tells us absolutely nothing about the impact of your hypothetical 15 pound bicycle weight difference on the qualities of a workout.
Here's the begging the question fallacy you've committed--
Me and everyone else: "If you do the following, you equalize the workouts"
You: "Assume we can't do those, I win the argument."
Assuming that all things being equal IS question begging if your basic argument is that things can't be made different to compensate for the difference in weight. All I've "conceded" is that if we assume you're right, then you are correct. I don't have any reason to assume this all things being equal has anything to do with reality, so I am not making that assumption, and am very clearly stating you are wrong.
So let's go back to your original argument--
"
No, you can't. You can achieve the same amount of work on any weight bike, but that doesn't mean the "workout" is the same. For example, if you bench press 300 pounds 10 times, you're doing the same amount of work as bench pressing 100 pounds 30 times, or 50 pounds 60 times, but they aren't the same workout, because the body responds very differently to them. Likewise, riding a 30-pound bike 1 mile is the same amount of work as riding a 15-pound bike 2 miles, but it isn't the same workout, i.e., it doesn't have the same effect on the body. Working with heavier weights tends to increase muscle mass while working with lighter weights tends to increase muscle endurance. Many people incorporate both types of workouts into their routine."
You've now had to concede that it's resistance, not weight per se, that matters, that gears can alter the relationship of weight to resistance, that hills can do the same, that weight bench logic has nothing to do with bicycle riding logic because a bicycle itself is a set of levers and pulleys that can be adjusted to duplicate the resistance effects of added weight, and that the relevant factor is actually time, not distance. (And that's not even accounting for the drastically increasing wind resistance when you ride at higher speeds). Also, that your calculation of the differences in work between the bikes was all wrong There's literally nothing left of your original argument.
.Have a nice day.