I think this is incredibly over-optimistic.
1) Cost per point per use of $10 is very unlikely. Even Aulani subsidized contracts are closer to $11 and absent a small dip during COVID they are cheaper than ever;
Clearly we're not talking purchase price today, but something acquired years ago. I have SSR points that are pennies above $10 per use.
2) "Likely a LOT came from large and cheap resale contracts." - this is clearly not the case as nearly all the listings being discussed are 250 or lower sized contracts;
I think you may have some of this confused. There are two different issues being discussed here. And you're confusing them or conflating them into one issue. (1) The Aulani contracts being dumped, which are mostly around the 100 to 200 point range. And (2) the person who has 8k points and is renting them out on the DIS boards. We don't know what point levels those points are at. But price speculation suggests that they could be larger.
3) There's no accounting for the transaction/acquisition costs in the above cost per point. While they could have minimized this as a buyer, it's not zero;
This is a fair point. I agree. But also amortized out over 35 or 40 years, this would be pennies per point use. A 200 point contract with a $600 closing cost with 40 years left would equal out to about eight cents ($.075) per point use. Again, if they're buying 100 point contracts it would be more, 300 point contracts would be less. I don't know how deeply this person thought through all this. But a set of large contracts at a very low PP rate would likely be the best path here.
4) The above assumptions are based on point rental prices going up at the same rate as annual dues. They have not thus far tracked that trajectory;
Fair point. Again, this is an unknown. I would wager that after new "lands" start appearing at WDW, rental prices will likely go up beyond inflation. Before that, yeah, things don't look awesome for rental. But again, that's speculation.
5) I think an average of $21/point is generous even if you might be "running" the business and renting direct (so you're not paying any commission). There will inevitably be breakage that will bring that down. Heck, the site with the largest number of these new Aulani listings is renting points for more than 10% below that for a glut of available reservations during the next 4 months;
Again, I think you're confusing two issues- the 8K renter is not attached to Aulani. This person has multiple contracts at WDW.
6) Any benefit you gain from deducting "business" expenses is swamped by the fact you're not paying yourself any salary in the above model.
Again, maybe. Depends on their situation. If you're an empty nester with a couple of empty bedrooms, using one as an office for a business likely doesn't detract from income elsewhere, unless you were going to rent that room, which most people don't. This would decrease business tax and potentially increase what was available for a salary or bonus for (presumably) the owner/employee.
All things considered, maybe you're making a 9-10% return each year with your principle going to zero in year 36. Not something I'd personally be interested in compared to other passive investment alternatives. Now, if you could also perfectly time an exit from the market such that you recouped a decent portion of that initial capital (rather than holding to year 36 and taking zero), perhaps there is something there....and perhaps that's exactly what we're seeing.
All this was was speculation as to how this could be a reasonable part-time job. Also, we're taking this person's word that they ONLY have 8k point, which is the maximum Disney allows across multiple resorts. Maybe this person has contracts under a couple of names. or business names. Again, the Aulani dump is a separate issue, but it's clear that business has significantly more than 8k points. Same could be true for the person posting on DIS.