If this were true it would be bad. Luckily it's mostly myth and rumor that doesn't actually line up with reality. The reason leasing cost is so low is that these vehicles and their batteries tend to be decent shape at the end of the lease and still have a good resell value. And they don't cause any issues in between.

With modern vehicles, the battery can actually be expected to outlast the vehicle. Many EVs sold 10 years ago still have their original batteries. They are fine and really good value if you can get a second hand one.

Battery replacements have mostly proven a myth for EVs. Of course they sometimes happen, especially with older vehicles with primitive battery management (e.g. no cooling). But most EVs ever sold still drive around with their original batteries.

Modern battery chemistries are actually even more durable. 3000 charging cycles is pretty standard these days. With a 300 mile range, that's 900000 miles. Most ICE cars don't make it half way that before ending up in the scrap yard. And that's usually after years of expensive repairs, inefficiently running engines, and going through lots of replacement parts. 3000 cycles is just the threshold where you can reasonably expect the battery to still hold > 80% of it's charge. It's not like it will stop working. Maybe 60% is still good enough. Some battery chemistries do way better than 3000 cycles of course. There has been talk of million mile batteries for some years now.

> 2 or 3 battery replacements would be a reasonable guess in that time frame.

It absolutely would not. "0 battery replacements" is the correct number in 9 years.

My Model3 is 6 years now, and has lost about 10% range. The car doesn't suddenly become useless either. I expect to keep the same car + battery for at least 20 years without replacing it.

> 2 or 3 battery replacements would be a reasonable guess in that time frame

There are reports of people getting > 600,000 miles out of a Tesla battery. The only vehicle where you're likely to need regular battery replacements on is the Nissan Leaf or it's sister the Renault Zoe.