Well said...........Maybe because of bandwidth limits on Amateur Radio? The Kenwood 940 & 950 had lots of mods that really make them Wide but those doing so did not make any friends on the air being 5kc's or even wider on transmit. I believe many of the new SDR's will also get Very wide but again you will make plenty of enemies. It's not like 11 meters where nobody cares. 3 kc's is pushing it to where it should be & most don't go over 2.9 which is plenty.
This FCC requirement is specifically related to DATA transmissions only, and not voice.
Last I recall it was 3kc wide on Phone in the USA. It's why technically if you are a Technician Class that you are actually pushing the limits if you operate say,28.300.00 because half of your transmitted signal would be Out of your authorized Band at 28.298.500 & the same for General Class or Advanced Class operators on their respective band edges. It's the same for either of those license classes. I was taught this as a Technician in the early 90's. I for one don't have any desire to sound like the BBC because I think their audio is Not very appealing & you can go listen for yourself & hear that it's nothing to brag about.This FCC requirement is specifically related to DATA transmissions only, and not voice.
(I'm not in the USA, so I'm not sure what the USA voice bandwidth requirements are).
In many parts of the world ESSB is perfectly legal and enjoyed by many, including me (and it is hated by some sad hams too! haha). The ESSB groups are a great resource for the type of modifications you are referring too. Properly controlled wide bandwidth SSB is not splatter. And it sounds incredible on a properly configured RX. ESSB works especially well with good SDR equipment also.
Where I am from it is used mostly on 160M and on 10m, where the bands are very quiet with lots of room for activities. You won't see it fire up in the middle of 20m during a contest, so everyone can relax.![]()