That's definitely not how physical property works.
I mean, there are implicit guarantees that don't have to appear in the sales contract, such as the requirement that the car will meet the applicable pollution-control regulations and won't actively try to kill me, but that's obvious enough. Did you have something else in mind, particularly vis-a-vis the batteries?
You own the car. You own the battery. No sales contract changes that fact of ownership. They delivered a 75kwh battery into your possession. Since it's your battery, you should be able to use your battery however you want without having to pay Tesla. People are rightfully upset by a PR move that proves that the manufacturer is treating a car that was sold and delivered as if it still belongs to the manufacturer.
The batteries are backed by a warranty, which in turn is part of the cost of the car. It makes perfect sense to derate the batteries in order to lower warranty costs. Of course, we can debate whether the consumer ever saw the benefit of those lower warranty costs, but the core idea is sound enough.
As for "legal title," you have "legal title" to whatever the sales contract promised. If access to full battery capacity at the expense of service life wasn't in the contract, then you're not entitled to it.