I agree the newer ones are likely better on average; but you may be over-estimating the problems that even the early ones have. Of course, like any car from any manufacturer, there are some that have numerous problems, and of course you hear about them (true for any car, but especially true for new tech). But the only problem I've had that needed fixing was the door handles - I have VIN 112, I and I think they really have replaced a majority of the door handles from the early models. And that was no emergency; we could still easily get in and out of the car.
Everything else they've done is something that didn't need to be done at all, and in fact on other cars I wouldn't have bothered asking a dealer to look at. Mostly quieting things down - like the sunroof and the HVAC. That may have been all that I've asked for; they have proactively replaced a couple of other things that worked fine, but they thought might cause a future problem. You generally don't have to drive it in regularly; they can just take care of it when you do the annual service. In fact my second annual service will be in a couple of weeks - and they will valet a loaner to me, so I don't have to drive in at all. The rotated my tires last year; this time they will put on new ones. I just have everything done at once. This has been no burden at all.
Of course nobody can guarantee what YOUR experience will be, but I think that's probably how it is for the majority. I'm not claiming Tesla's failure rate is better than others; I just think in most modern cars the failure rate is so low that many people overthink the issue - they think it is higher than it is after listening to a series of anecdotes. People ask this sort of question in all car forums. With any make you might get a lemon, but very likely you'll have a good solid vehicle.
After re-reading this, it could sound like I'm scolding you for asking the question. That is not my intent at all; it's a reasonable question and you asked it very politely. I'm just trying to indicate that you will most likely be satisfied with this aspect if you take the plunge. If I were you I'd spend most of my time making sure it fits in my garage and budget, making sure I have capacity to install an EVSE, and making sure it's suitable for my driving needs. You are not likely to regret your purchase (the Model S has the highest customer satisfaction rating ever recorded); but if you do I suspect one of those issues will far more likely be the cause.
. FWIW, service appointments still pushed out a bit in the SF area (e.g. Palo Alto)...not quite as lonely as the Maytag repairman yet...
