Well Teslas goal is to accelerate the turn over to electric cars. They don't have to be perfect and become 100 years old. Just making enough trouble to the other car manufactures to switch over to electric cars.

I've payed 4000€ in 2011 for a Model S reservation, and got my Model S in 2013. Late but I got it. And I've payed another 1000€ to reserve a CPO Model X in 2017 and got it a few weeks later. Both cars had their little problems, but all of them had been solved under warranty and they're working fine till today.
Yes Tesla is slower than promised and nearly never had been reaching its goals in expected time range. But they reached it. And even Model 3 will be delivered. Of course later than promised, but I'm sure it will be.