Earlier quoted context omitted.
If anything the cumulative patch is better, not worse. It's much harder to validate nine individual patches than a single cumulative update. What happens if patch seven fails? How about six? How about six and seven? There are an exponential number of failure cases with multiple patches vs one.
What are these security fixes that they fail so much? Although there are of course tough bugs with tough fixes, the vast majority presumably consists of off-by-ones, simple buffer overflows, use-after-free, etc.
I think the cumulative patches work fairly well, they install much faster than the old ones. I am however troubled by the amount of security fixes Microsoft has to do every month. This shows that security is mostly an afterthought at Redmond.