With insufficient power, you sacrifice altitude rate or airspeed. If you're already near the drag bucket, which should be on the order of 1.3 Vs, sacrificing airspeed to maintain glideslope will increase your drag - wasting precious energy - and assure you will land shorter with a higher rate of sink.
You could even draw a graph: beginning at 500 feet, on-glideslope, on-speed, power off.
Plot one line where you maintain speed while your descent rate (4 degrees, for example) is steady until reaching ground effect. You then have energy to round out in a flare. If you see obstacles, you just might have the energy to zoom up and over. Remember "Stick and Rudder"?
Plot a second line on the same graph where you maintain glideslope as speed bleeds off until stick shaker, then try to recover. You will be out of airspeed, trimmed nose up, and out of energy, with a sink rate that...
The second line is apparently what the autopilot followed on both THY and BA 038.
GB