"Richard Kaplan" wrote
My experience suggests decimal dust.
I think it is hard to know how many accidents are due to maintenance issues
by reading NTSB reports

I concur, and do not base my opinion on NTSB reports.

Anecdotally I hear about a lot less engine failures among people flying
engines within TBO by hours and also under 10 years

That's because few airplanes reach hourly TBO within 10 years. My
experience indicates that those engines fail about as often - there
are just fewer of them.

it would be interesting to tabulate the data someday in a
statistically valid manner.

Yes it would. The very fact that the manufacturers COULD do it if
they chose, and choose not to, indicates that they don't want the
facts known. That suggests to me that the failures (a) happen far
more often than is generally believed and (b) are not prevented by
regular factory overhauls.

Fundamentally, I think most failures are a design problem rather than
a maintenance problem. So why are we still using clearly obsolete
designs? FAA.

Michael