The requirement for 180 minute ETOPS is 0.02/1000 hours - or 20 shutdowns per million engine operating hours.
The engine types on the 787 (Trent 1000 and GEnx-1B) are both running around 2 per million hours, or about 10 times better than the 180 minute ETOPS requirement. Such a high level of engine reliability is pretty much unprecedented for introduction of a new engine type,
Like I said before, the 787 has it's issues, but engine shutdown rate is NOT one of them.