vs. "Hey, we have this great sale going on. What, new model? Naww, we are just having a sale!!"
The incumbent MFG's literally have "new inventory" sales on their last-years model to clear out inventory. They let you know well in advance that a new car is coming with new features so you can make an informed decision.
Is this not what "hey this 1-2 year old model is on super duper sale right now, it's really cheap, you should buy it!" means? Is a steep discount on older stock not always code for "better shift these before new model comes out"?
You see Apple fanboys fall for this one every time, too. "Yay I got a new iPhone 5 last week and it was SO CHEAP, I'm a genius... wait wtf they just announced the iPhone 6."
The upstart, by virtue of simply not yet having that many potential repeat customers around, is targeting first time buyers. The goodwill created by having as little obsolescence as possible far outweighs the extra sales they might get through it. This tradeoff changes significantly once a company is established and the number of potential repeat customers is high. Now it's always a balance between repeat sale likelihood and repeat sale cycle duration.
Different forms of obsolescence have different effects in different markets. E.g. unlike smartphone makers, car manufacturers tread very carefully when it comes to longevity. Red book value and all that. So what do they do? They have perfected the generational model update cycle. New generation cars are literally designed to make the predecessor look old, because that is the most acceptable repeat sale driver. Tesla just isn't there yet.