To help some understand why the Model S could be "cheaper" to own vs a Honda Odyssey it's important to understand a few factors:
1. Low fuel costs - electricity is way cheaper than gas and when you factor in gas savings over 8 years, you get substantial savings (ie., $20k over 8 years if driving 15k miles a year, of course depends on gas prices and electricity prices).
2. Low maintenance costs - there's no oil changes, timing belt, etc. It's basically tires. Even brakes you don't need to change often because of regenerative braking.
3. High residual value due to upgradeability - the battery pack is swappable, so after 8 years (or longer) you can swap out battery packs to a bigger pack (ie., 400+ mile range). This is a great feature and will add residual value to the Model S. Also, over-the-air updates keeps the software always up to date.
4. High residual value due to battery pack - the battery pack for the Model S is holding up well with customers so far, and after 8 years it should show minimal degradation (ie., 10-15% likely, max 20%). In other words, the battery will still hold substantial value and when a person buys a 8-year-old Model S in the future, they are not only buying the car but they are buying the battery pack (ie., fuel savings) as well. This is why the residual value of a Model S (or another EV with a large battery pack) will be substantially higher than a comparable ICE car.
It's wrong to think that the majority of service costs as vehicles age is in the engine and oil changes. Most new cars engines/tranmsmissions will go very large distances with no mechanical failure if serviced properly. Exceptions exist, but for the most part, engines are durable and have minimal service requirements.
Cars must have suspension replacements, plus fixed for lots of little car systems that can start failing with age. An example is windscreen washer systems. Usually required for safety inspections, they can stop working, and it's expensive to remove and replace them because they wind their way around multiple components. Same for hvac systems and lighting systems and on it goes.
I bring this up because the worth of a tesla will not just hinge on the ability to fit a new battery pack and go. It will also hinge of the ability of the basic vehicle and non-propulsion systems to continue to work and become economically serviceable. Most cars can get a substantial mechanical refresh for the current cost of a new tesla battery - but this is not usually done because the car itself develops many other failings and a new one is faster and easier to purchase.
So the resale value will swing on not only the battery replacement cost, but may other things besides. Only then will we know what the used value looks like.
I think the parent poster is making an "all things being equal" comparison, where all of the things you mentioned should be equal when comparing to a car with an ICE.
For example, both the Tesla Model S and a Honda Oyssey will, presumably, require suspension replacement after a similar term when driven on the same roads by the same person. Likewise for windscreen washers and other sub-systems. Given the level of engineering and attention to detail in the design of the Model S, we should expect these systems to be of equal or greater quality than their traditional motorcar equivalents.
The point is that it appears the EV components won't negatively impact residual value as many EV-naysayers have been touting all along. "Just wait till that expensive battery pack only takes half a charge in 3 years!" That's the kind of sentiment that the parent poster was refuting.
I've heard the "low maintenance costs" point made often by Tesla themselves, but based on my research from their website it doesn't hold up. Tesla encourages you to buy their $600 a year service inspections[1], and their $1,000 a year extended service agreement. And God forbid anything breaks outside of the warranty, because you'll be in for some costly repairs[2].
Or, battery packs will degrade and people would not value them at all.
And, more importantly it's very unlikely that Model S will hold any residual at all, especially in 8 years - it's essentially version 1 of technology (with Roadster being beta version). In 8 years Tesla itself will have version 3, or may be even 4, and version 1 will be just obsolete. Notice how people buy new Camrys instead of 8 year-old 740s.
"A Battery Replacement Option will be available for purchase soon. The option allows you to pre-purchase a new battery to be installed after eight years for a fixed price: $8,000 for 40 kWh batteries, $10,000 for 60 kWh batteries, and $12,000 for 85 kWh batteries."
1. Low fuel costs - electricity is way cheaper than gas and when you factor in gas savings over 8 years, you get substantial savings (ie., $20k over 8 years if driving 15k miles a year, of course depends on gas prices and electricity prices).
2. Low maintenance costs - there's no oil changes, timing belt, etc. It's basically tires. Even brakes you don't need to change often because of regenerative braking.
3. High residual value due to upgradeability - the battery pack is swappable, so after 8 years (or longer) you can swap out battery packs to a bigger pack (ie., 400+ mile range). This is a great feature and will add residual value to the Model S. Also, over-the-air updates keeps the software always up to date.
4. High residual value due to battery pack - the battery pack for the Model S is holding up well with customers so far, and after 8 years it should show minimal degradation (ie., 10-15% likely, max 20%). In other words, the battery will still hold substantial value and when a person buys a 8-year-old Model S in the future, they are not only buying the car but they are buying the battery pack (ie., fuel savings) as well. This is why the residual value of a Model S (or another EV with a large battery pack) will be substantially higher than a comparable ICE car.