Ian Woollard wrote:

b) the testing regime more or less guaranteed that the first few
launches would end in disaster- this was a very bad move politically as
it made it look like the program was making bad progress. (Note that
they had a test program of something like 12 launches, but only 4 of
them actually happened.)

c) the engines and other components weren't sufficiently well tested
individually

If memory serves, they did not test the full rocket in any way except
launching it a few times ... with the known results. They did not have
fund allocation for it...

Robert Kitzmueller