The vast majority of people buying a Tesla today will never need to replace the battery. The chemistry used in electric vehicle battery packs these days have much better longevity than what you see in most other lithium-ion cells.

Over the timespan in which you'd have to replace it, and given future cost reductions in battery production, it's probably the same as the total cost of maintenance for a petrol car. The cost of getting a petrol car to 100k or the 10 year mark isn't cheap. Even a Toyota is going to run you like $5k. A BMW or Benz, probably closer to $15k. If you buy a used BMW 3 series for $20k today and keep it for 10 years the cost of maintenance + gas will be well over $20k. A lot of people greatly underestimate the total cost of ownership for a petrol vehicle. Best case scenario is you have to replace every moving part that isn't the engine itself. Worst case scenario is you have the replace the engine too.

Actually, you'll probably never need to change the battery as "the latest data shows less than 10% degradation of the energy capacity after over 160,000 miles on Tesla’s battery packs" [0]. Even if it degrades like 50% by the time the rest of the car dies, there will probably start to emerge a market for the old batteries to use them for grid storage where kwh/weight does not matter as much so you might even get some of your money back.

[0]: https://electrek.co/2018/04/14/tesla-battery-degradation-dat...

...then they would also include the costs of maintaining an ICE.

I feel by the time you need the battery changed out, hydrogen fuel cel would be the new norm, and it will be not that difficult to retrofit an electric car to fuel cels.

It makes no sense either way.

CapEx and OpEx are different animals.

It is still a savings as you would have bought an ICE otherwise