The sequence of events with the strut being weakened which then allowed the booster to puncture the H2 tank is pretty much the was I remember the report reading.
It is also worth remembering that statistically, the shuttle was likely to fail on something like 1 in 100 missions. Wasn't the recent one something like #107? I am not sure how much of the shuttle is 'new' each time it flies, but for sure it is pretty much gutted and rebuilt with broken bits being replaced. When there is talk that the shuttles are old and dated, its more a case that if the project was done now, the result would have been very different.
As TrickyWoo has said,'previously acceptable risks have become unacceptable over the last two decades'