All Breathing Techniques is just Wind Breathing with extra steps
I think we all know that the elements that are seen in the anime/manga are not actually being created. However, one of them seems to be the exception, and that is none other than wind breathing. Sanemi seems to be able to swing his sword so hard, and actual wind is being formed which slices and shreds it's opponents. However, if that is the case then... wouldn't that make all other breathing forms just wind breathing?
Exhibit A: Beast and Mist Breathing. Okay so these are the easiest to connect to wind breathing since they are derived from it. Muichiro was able to use third form and Inosuke was able to use 10th form to blow away poison and ice respectively. Mist and Beast = Wind breathing
Exhibit B: Love Breathing. This is where things get interesting. Now, we see that Mitsuri has a very long sword, however it isn't THAT long compared to what is shown. Like her sword in her 5th form seemed so long and it was able to shred Zohakuten's wood dragons like that, but her sword is only like a few meters max, like how was it able to extend to the point of making a tornado of slashes to destroy all the dragons... wait, a TORNADO OF SLASHES?! Perhaps her sword never extended, actually blowing wind so hard it creates slashes, just like WIND BREATHING. Love = Wind breathing
Exhibit C: Water breathing. We see that Tanjiro uses water breathing for a while. One of the most interesting times was against the swamp demon. In order to kill them both while in the swamp, he had to use 6th form Whirpool, a twister of slashes... hmmm where have we seen that... perhaps 4th form of wind breathing, Rising Dust Storm... yeah water = wind breathing
Exhibit D: Flame Breathing. In the Mugen Train movie, we see Akaza use Air Type against Rengoku, an invisible shockwave that traveled through the air. In order to block it, rengoku used 4th Form Blooming Flame Undulation. However, it seemed weird. even after the slash, it seemed like the flames blacked the Air Types, and we know the elements aren't real, so how could that happen... unless the slash created a wall or WIND TO BLOCK IT. Flame= Wind Breathing
Exhibit E: Stone Breathing. Slight spoiler for those who have yet to read the manga. When Gyomei first arrived, he was spinning his ball n chain around, and Kokushibo said he was drawing the air towards him... DRAWING THE AIR TOWARDS HIM. Stone = Wind Breathing
Exhibit F: Sound Breathing. it has been stated somewhere (i think) that Tengen's able to slash so hard it creates shockwave. SHOCKWAVES that blow AIR! Sound = Wind Breathing
Exhibit G: Sun Breathing... Okay I think I'm getting to a point where the "All Breathing Techniques is just Wind Breathing" thing is starting to fall apart... like what is there in sun breathing that makes it wind breathing. I can't really think of anything. Also can I just rant on how tf is Solar Heat Haze incorporated into the Hinokami Kagura Dance. Like what is the point of extending the blade. In fact, how does the blade even extend... unless it is it is actually a blade of AIR!!! Sun = Wind Breathing
Exhibit H: Thunder and Insect Breathing... so what is there that makes these wind breathing... hmmm... honestly no clue... I mean, Shinobu feels so floaty so it would seem perfect. her floating around also kinda reminds me of when Zenitsu was flying around with Daki using godspeed... wait... floating and flying around... in the AIR! Thunder and Insect = Wind Breathing.
Exhibit I: Flower and Serpent Breathing... yeah there is literally no explanation I can find really... but if we look at the people who use it... we have Obanai and Kanae... Obanai is Sanemi's Best Friend and Kanae is Sanemi's Girlfriend... who is the WIND Hashira... so... Serpent and Flower = Wind Breathing (Yeah i really couldn't come up with a good explanation, if anyone want to, go ahead)
TLRD: If all breathing forms don't create their elements besides Wind breathing, then All Breathing Techniques is just Wind Breathing with extra steps.