This is off the subject of small turbines, and the original point was
the theme of sustaining vs. disruptive technologies.

ETOPS is a sustaining technology.

More than that, it's a methodology more than a technology. Most
shutdowns in flight on four engine airplanes were discretionary: a
variable was observed out of bounds and the crew elected to shut it
down because it seemed more likely that the engine might inflict
damage on itself. With ETOPS this is a big no-no because if an airline
has so many inflight shutdowns they lose their right to fly ETOPS or
it is restricted.

ETOPS engines are not more reliable physically. The maintenance
requirements are different to eliminate certain past issues, and
operators have a big incentive not to shut them down and not to fail
to maintain them so they need shutdown.

The real issue with ETOPS is that you have the issue of an aircraft
the size of a 777 which may have to complete a long segment on one
engine, descend, and maybe shoot one or more missed approaches. Maybe
onto a slick runway. That's a lot of asymetric thrust and reverse
thrust as well..

Sooner or later, the bottom line is, we are going to lose nearly four
hundred people in one whack in a 777. No one, myself included, wants
this, but there has never been a commercially marketed airliner made
in any quantity that hasn't eventually had a catastrophic total loss.
IF that crash was in any way perceivable as a consequence of its being
a twin rather than four engine crash, heads are going to roll. Boeing
will likely have a judgment on their hands that will make them wish
they'd built piston singles instead, the operator will be in big
trouble and there will be regulatory changes and possibly a new
Administrator.