I don't think that's a fair comparison; I'm sure they had a plan for mass-scale production for model 3 from the start, the problem is if that plan/approach will

I don't think that's a fair comparison; I'm sure they had a plan for mass-scale production for model 3 from the start, the problem is if that plan/approach will work or not in a reasonable time. The non-scaleable stuff was most likely done in parallel not to delay initial deliveries, they don't need to validate the product idea.