From my experience, fixing a major issue with Tesla almost always involves multiple visits. Even if the SC is willing to pick up the car with a flatbed, you usually still need to go in and chat with them (not always, but at some point you will need to go). Typically, the first visit they will diagnose what's going on and attempt to fix. But with big issues, they often can't fix in the first go. This means going there, waiting a few hours, then heading back home, likely without your car. If this is a total 400 mile round trip, you're looking at the better part of a full day. Ok, now you can head home... if you're lucky, you'll get a loaner, if not, you end up with Uber credits. But if you're 200 miles from a SC, it's likely you're in a more rural area - this means significant wait times for an Uber. That's just to get home. If this is your only car, you still need to run errands, get to work, etc. This means waiting 30min-1hr for an Uber anytime you need to get anywhere.
From there, they'll need to order the parts (almost always takes 2 weeks+). Once the parts arrive, they'll attempt to fix. They'll get it installed and ask you to come in... 400 mile round trip scenario is now in play. Once you get there, depending on the issue, there's a not-insignificant chance that the issue won't actually be fixed or a new one will crop up. There are many reports on this forum where people get notice that their vehicle is fixed and ready to go, arrive at the service center, just to immediately find out that it in fact, was not fixed. It seems like most departments often define "fixed" to be "task/install/swap complete", and not necessarily "original symptoms and issues gone". It's not uncommon for this to happen and the SC will then take the vehicle back again, rediagnose, and order a new part. Again, 2 week wait to roll the dice if the new part actually fixes the issue.
Rinse and repeat until issue is finally fixed. Yes, they can tow using a flatbed, great... but that's nowhere near the full picture.
Don't get me wrong... the above "worst case" scenario is probably not going to be the experience every single time - it's really more of a worst case scenario. But at the same time, it is not wildly improbable either as I've heard many similar stories. Chances are you'll have one or two big issues come up in the first 5 years of ownership and you'll have a degree of the above experience each of those times. To me, this seems like a major hassle, but I love my tesla and would be willing to go through this a couple of times if that's the price of admission. But not everyone is willing to do so and you'll have to make your own judgement call on that.