I suppose you can keep the 2400 fpm descent rate going and decelerate if you add flaps just as you get below each max flap placard speed, but this is usually not what is preferred.
Indeed, frowned upon and I doubt very much you could achieve the performance you speculate on. There is not enough drag in the flaps to succeed in that.
Flat Cap: I can only tell you what I've observed. First some basics, which Avenger has touched upon. VNAN PTH is an energy profile not a strict descent profile like a glide slope. If you are descending towards a WPT with an ALT/SPD constraint the ALT has priority at the sacrifice of speed. When descending to 250/100 then 250kts has priority.
The forecast winds entered on DESC page help with the calculation of TOD but are then not updated during descent, automatically. If the real world & winds are different the a/c will try to stay on the calculated path profile and the speed will be sacrificed. You can update the FMC to actual wind by reselecting DGT TO the active WPT and this actual wind is now used as if it was at TOD from np]ow to landing.
When decelerating approaching FL100 it generally goes 500fpm if on an accurate path and accurate descent speed. If the speed is higher than FMC speed it could even level off at FL100. This can cause you to go high. It could then dive for the path for the next WPT constraint and accelerate above 250kts in doing so. You'll have seen 2 green rings on the map showing the calculated start & end points for decel to 250kts and then continued descent.
The next green ring you'll see is DECEL. This is the calculated point where F1 is expected. Assuming this whole profile is flown in VNAV PTH with A/T as you approach this DECEL marker you'll see the ASI speed bug start to reduce towards UP. The a/c goes 500fpm to decelerate. If its got it correct you should hit DECEL at UP - UP +10kts. Taking F1 s now your decision. The FMC has calculated the reduction in energy from this point in space to achieve the next constraint which maybe IAF or OM. You'll see the SPD/ALT in LEGS. There are no more DECEL rings, but you'll see the ASI speed bug reducing and you are supposed to match the flap setting as the speed bug reduces below flap man speed.
It is a real gotcha if you forget the flaps and end up slow, but there is a speed buffer between Flap Man bug and absolute Min Man speed; that is why it is very common, IMHExp, for many operators to either not use VNAVPTH below FL100, or t go SPD INV. You then control speed and not FMC. A variety of reasons: it improves your direct control of the a/c; the ATC route may not be the same as FMC route and so the energy profile will be different.
But it ain't calculated on using flaps at max speed.