Snow Dog
I'm sure you're right. However, the unwritten assumption behind your comment is that all aircraft and equipment as supplied by the makers will always fail "safe". Sadly, many years of experience prove that this ain't the case.
The aim of the manufacturer is always to turn the biggest profit, while delivering kit that just meets the Spec. The aim of T&E is to check that, first, it does meet the Spec (not always the case!) and secondly, that it can be operated safely and effectively. Only at that stage can it go to the OEU for them to find out "how" best to do the job with it.
In my days at Boscombe (several decades ago now, alas!) there were no OEUs. This meant that our only direct link with subsequent users was through the inappropriately named Handling Squadron. I say inappropriately because the unit did no "handling". It was an office job, putting together Pilots Notes/Aircrew Manuals from paperwork generated mainly by the makers and to a lesser extent by Boscombe.
I was delighted to learn of the creation of the OEUs, as they provided that "missing link" between T&E and the users. How sad that this obvious benefit has gone unappreciated by the decision-makers.