pitch/power
Gentlemen (and ladies)
Am surprised by your confusion. On a light aeroplane without much in the way of excess power and certainly very little inertia then the favoured technique was always to control the speed with pitch and the rate of descent with power. I was taught this in the airforce and taught it myself. Can you imagine, however, just how uncomfortable this would be to your pax in the back of a highly powered and heavy (ie loads of inertia) widebody jet?! Remember, inertia is the reluctance of a body to change, in this case, its speed and would need a pretty impressive pitch change to achieve this effectively in, say, a 200 ton aeroplane. We all, probably instinctively, point at the aiming point and use thrust to achieve the desired speed on anything from a turboprop upwards. It is just that you have 'forgotten' that you do it and you do it instinctively. It is also true that power and pitch are totally inter-dependant so that,although both methods work out, only the thrust equals speed and pitch equals descent rate is the really appropriate method to use for large inertia aeroplanes.
I'll standby for some flak.....