Elon was the one who said they put too much new tech in the Model 3 at once.
I may have missed something, but, I haven’t heard that myself. What I did hear was Elon saying too much automation at once in the machine (production equipment) that builds the (Model 3) machine. Yes, another example of trying to do too much too fast, but, I do see it as some amount of learning from the X experience reflected in what they did with the design of the 3 itself. So, some learning after the X, but wasn’t generalized so much to the production process. I think we’re well aware that pushing the envelope is a well developed tendency with Elon.
Fortunately, we got commentary from Elon not too long ago that others at Tesla had persuaded him to dial back ambitions re automating the Model Y production process (I think this happened even before 3 production ramp got rough).