Hi,
SNs might still be considered expendable test articles at this stage.
Today's SN4 blow up is both bad and good news. Bad news for obvious reasons. Good news in the long run, as SpaceX learns the hardest possible way whatever may go south. Yes, there are problems that must be fixed. SpaceX are building their engineering confidence while testing and solving, incrementally, problems associated with each of these early catastrophic experiences. As pioneers did, between the 1940s and 1960s. Engineering insights gained from this process is invaluable. Ultimately, a refined design will end up in a better, safer vehicle.
SN7 segments have already been spotted and SN construction keeps running at an unusually high pace by any other standards.
So, it takes 20 more articles before a successful flight occurs, I'm still fine with that.
A.