There shouldn't be any doubts, it's definetly will not be 2023 and its not the point.
Everytime Elon mentions date, media just takes it for granted and repeats itself everytime the deadline is missed.
In reality, if you have only broad understanding what is needed to be done and you can only make assumptions about how long it will take, you still need to target some specific dates and try to stick to them even if more often then not, you will miss these deadlines. In this case its the date if everything would go to the plan perfectly. But we are not living in the perfect world and who knows that difficulties could accur or how long they could take. How you can incorporate these in your predictions?
Its very difficult to properly predict big projects and this type of projects are in scale which is even more insanely difficult.
You might want to listen to the livestream -- Elon answers a question from the press about how certain the date is, and basically says the same thing you just did.
When Kennedy gave his moon shot speech, he set out a deadline. At that time, space travel wasn't even a thing and had to be invented. He could have said in our lifetime. He could have said someday. He said in "this decade".
Setting an arbitrary deadline is not a negative. It gives people goals to achieve vs infinite discussion/research. Even if the date does get pushed, it's not the end of the world. NASA is famous for its schedules getting pushed. When's the JWT launching? When did the Hubble launch? How far behind was the LHC? Yes, people complain, but I would rather have them late and working than rushed and not. Look at what Hubble has given us. Well worth the wait.
Not sure why Elon Musk gets so much hyper focused attention like this. He's not the only person to have projects run late. Look at the Red camera system. Look at Black Magic Design. Apple, Microsoft and pretty much any software dev has had to push back release dates. Any HN reader should be sympathetic as I'm sure everyone has had to push back release dates, or at the least not release every feature as scheduled.
I'd love to see it happen on schedule but I have doubts.