Well ... everyone's entitled to their opinions. But I'll say this. I traded off two nice vehicles in order to be able to afford to purchase a used Tesla S recently. And I have no regrets.
The people who keep complaining about the Tesla's "cheap interior" or build quality must be comparing it to some really high end luxury cars? Because I'd say this Model S has superior quality to cars I've owned previously like my 2016 Nissan 370Z NISMO edition, or my Jeep Wrangler Rubicon Unlimited. It's probably most comparable to the 2011 Cadillac CTS Coupe I owned, which I don't think is bad at all. (Of course, some of the Cadillac owners on the message forums complained that the CTS didn't have comfortable enough seats and so forth, too. So yeah, you can't please everyone.)
I'm not so much a fan of the new Model 3, with pretty much everything placed on the touchscreen (AND that screen looking like it was stuck there after the face, vs integrating it cleanly into the dash itself).
I'm definitely interested in what Apple brings to the table for the electric vehicle market, though. One of the glaring omissions with the Tesla is the lack of ability to really integrate with a smartphone. There's no "Apple CarPlay" or "Android Auto" type functionality at all. It's more of a proprietary selection of Tesla-designed apps, beyond your basic Bluetooth connectivity for hands-free calling and ability to play songs off the phone's own storage.
I have my doubts I'd care much for the styling of an "Apple car" if they really built such a thing. Their minimalist tendencies that work nicely on computers and portable electronics aren't necessarily what I prefer in a vehicle. But they're very good at user interface design and that's where they might really make a good contribution. Auto-makers are notoriously BAD at getting technology right in their vehicles. I just drove a new loaner Infinity QX60 SUV and the stereo sounded poor. The controls weren't user-friendly at all. And there were just odd decisions all over about how to best use the screen space available on the dash.
And even on the Tesla, the operating system and software seems less stable than it could be. It's a pretty common thing that Tesla owners tell you they have to do a system reboot by holding down both left and right buttons on the steering wheel, because things quit working right or responding on the dash.