The training system has been revised by one of the TRE's, is much better than it was at least on the 777.
The failure rate is low, most fail because inadequate prep or because they plain struggled through the whole thing. The odd trainer/checker still exist who do not follow the training syllabus. But to be honest they are rare and well known by the training hierachy. Best dial 2 if you get one of them on the check LOFT. Just my 0.02 fils.
You would probably get an accelerated command once past the 8000hrs mark, with 2000+ hard time on aircraft over 55k tons. This is correct at least for the present time on the 777, but can and does change, be warned.
EGGW