Virtually every game on the market stays within the 30-48 range, and they all have no problem. If you have a problem with that range, you are doing it wrong, and you have some other part of your engine to fix.
maybe virtually every FPS or any game with slow moving actors.
Physics integration rate, again, is a function of system stiffness (ie. if you have spring/damper systems like the one needed for race cars, you need to solve them at high rate to avoid explosions) but this is only part of the problem.. you need to take into consideration the speed the game objects move: if you have a race car cornering at 150kmh and you are integrating at 30Hz as you suggest, you'll have your tyres traveling 1.38 meters between each iteration! Missing every bump and information available in those 1.38 meters by simply "flying" over. That's simply unacceptable for a huge number of game styles... such as racing and flying sims.
Since the OP doesn't give any details about his game, and he calls it "simulation".. your claim that 48Hz should be enough for everybody is simply not true... maybe it's enough for the kind of games that you are used to work on.. but that's where your claim starts and end.
EDIT: One more note about input responsiveness. Again, for game such as driving simulators, running at >100Hz is essential for control and feel of the car... driving controller input at 30Hz or at 100Hz is like NIGHT and DAY from the driver feeling point of view.
EDIT 2: You refer to my software as "small game", so it doesn't count. Would Forza Motorsport be considered a "big game" by Mr. Spiro? Well,guess what? It clocks at 360Hz for the physics. Link: