Hmmm, the poster must have worked for operators with rather poor maintenance/performance.
Well I worked on said Tristars for a few years, and I thought we were OK.
May I add we were departing from MCT in the summer at around 40degC, under British CAA rules. Even the good engines are not producing 100pc at that temp.
I remember it well because it was my first (of two). As an airline we only ever did five (in the 10 years I was there), and we never changed an engine away from base.
The reason for the low ferry time, was the small amount of fuel on board. I believe we were limited to 18 tons?
It wasn't until I had boroscoped the two engines and pronounced them fit that the F/Eng explained the lack of a V1. You didn't have climb performance on one engine until a few minutes after take off! Then they would not let me get off. I thought it was very dodgy, and was all for staying there a week to change the engine.