You're definitely right about how the developers don't really support a competitive scene. I hear from other people that the infamous Bigs tournament tanked a promising competitive scene, but I wasn't around then so I can't attest to it.
You're also definitely right about Chivalry being marketed towards a more casual crowd. I bought Chivalry after watching one of those "LMB lame" "n00bfest" facecam variety gamers. As a competitive player now, I cringe, but I understand that they are fun to watch for someone who doesn't want to delve into a game with a high skill ceiling.
So Chivalry was made as a casual game in mind, but that doesn't preclude competitive players from making a scene. Drags, reverse overheads, rainbows, waterfall moves, and butterfly unicorn chestnut tree whatevers weren't planned (my guess). Competitive players came up with those (Interitus had some great innovators I've heard). These techniques (and much much more) allow competitive play to exist.
You're absolutely wrong about the state of the current comp scene however, and I take issue with it. Not only because it's baseless and unfounded, but because it's counterproductive to what some people in the scene are trying so hard to do. Telling "noobs" and "pubstars" and "casuals" in official servers that there is no comp scene is actually what thwarts the growth of the scene.
It's definitely not the "same 100 people" and "same 5-6 clans". I know from personal experience:
Apex, Crimson Elites, Kila, Knights Templar, Loverboyz. These are clans that I saw around when I was casual, and died out when I entered competitive. Some of the players in these clans moved on, but a lot of them quit. When's the last time you've seen apex | PanicRageGG in a scrim? I face ♂ | curly and ♂ | Firegiant in scrims but I don't know how much of the other Loverboyz are still active. Not to mention that I saw |KiLa| Leafynoms in a scrim the other day for the first time in ages.
Bellator, Equilibrium, Genesis, God, Moorland Skirmishers, Nemesis, Valor. These groups have either (1) brought in casual players into the competitive scene, (2) were casual groups and turned competitive, or (3) started out with no competitive experienced. And yes, these clans scrim a lot. It's been slow over the holidays but Nemesis scrimmed Bellator, Genesis, and God multiple times in the past week alone. Equilibrium has taken the burden of recruiting new players in the past, but recently Genesis and Valor have taken the mantle (and we should commend those clans and their leaders for it).
There are members of Faucheur, Tempest, and Legion that I have never faced in matches because their roster has changed over time. I wasn't around to see anyone from Valkyrie but I know they were active before I was in. Also, Vanquish has returned to the comp scene and are practicing constantly. They turned down a scrim once because they were too busy in practice.
The point is that competitive Chivalry is not dead. It is alive and growing. There have been tournaments recently although it slows in the winter season (Thanksgiving, midterms, finals). New players are entering constantly and old ones are quitting slowly. No, we don't have weekly cash prizes or aren't sponsored MLG, no it might not be as big as it used to be. But unless you are scrimming weekly and are participating in the scene, you have no basis to say that the scene is stale.