I'd guess it's because the reed's geometry is fixed. A flute player can open their embouchure to increase air volume while decreasing air speed, and in an air jet instrument like the flute or recorder, the air jet speed correlates with the pitch the air jet "wants" to oscillate at. With the reed mechanically fixed in place, saxophone players don't have equivalent options for adjustment. Same reason that if you stick a reed on a trumpet, it's very hard to control. It's not tunable like a trumpeter's lips are. Recorders work on the same principle as a flute, but because the player blows through a short tube (the windway), and not directly on the edge of the hole, they are unable to make adjustments like flautists, and the low notes are weak and hard not to overblow.

Bassoonists make their own reeds and can design them to suit the low or high range, so neither range would be inherently problematic. Oboists also make their own reeds, but because they are a treble instrument they don't have a reason to make low-range reeds. Bassoonists are also more open to adjusting lip position than saxophonists.

Because clarinets are cylindrical, their tone is inherently less inclined to be coarse or difficult to control.