Well it has, there are just several different linux audio subsystems that coexist, and most distros prefer to let users expand the system of their choice rather than bloat the system from the get go lol.
It's super fresh software though, look at the github page (https://github.com/falkTX/Carla/), the source is last updated on March 2nd, which is yesterday lol.
If you're into that though, which only you can decide for yourself, using a real-time plugin host opens the world of pro grade "boutique" equalizer emulations to your audio experience, plus, and this might interest you more maybe, allows for the use of plugin analyzers and deconvolution tools, to create a near 100% ideal rendering and soundstaging without spending 40k on gear. It's pretty easy to use plugins, it's even pretty easy to write plugins, the LV2 API is pretty good and it's just C or C++, so pretty straightforward if you're into that.
I know that it's a different ballgame than bass and treble EQ knobs lol, but it costs nothing and the experience is high end craziness. Like I said, if you're into that of course. But I would certainly suggest trying it out.
Users who are not into corksniffing audio, can benefit from using a real-time plugin host for two things in my opinion:
1- If you watch multimedia, especially movies, you can use custom compression to really make the sound alive and to even out the volume. The deprofessionalisation of multimedia production because of the consumerization of multimedia production tools has lead to roughly 90% of all multimedia online (including that from big classic studios) to be badly mastered, and all different kinds of compression only make it a lot worse. A dynamics plugin that sounds good to you, which is a matter of taste, is an easy and very good fix.
2- The listening experience of modern multimedia is not so good. It's like HDR photography, exciters, EQ's and other plugins are added without good monitoring or without crosschecking on different renderers, compression codecs then add transient peaks which resolution conversion or variable bit rate compression then amplifies and things starts to sound really nasty. To listen to one song like that is bad enough, but it won't kill you, but to listen for a longer time like that, will be headache or at least fatigue inducing, and that "digital" sound character is nothing but transient unresolved peaks that clip away as if there was no tomorrow. Those might not be individually resolved by your brain in a recognizable manner, but they do pound your ears and cost your brain extra to blend them out. Using a dithering plugin with some clever dynamics shaping, makes for a 1000% better listening experience in long listening sessions, but also just to make the best of the content, even if the content is not so professionally mastered. An example of this is upsampling in audacious with the simple plugins there. The actual plugin will dither the signal while upsampling, mitigating digital noise, and the result will be a far better listening experience. Of course upsampling is not adding actual audio information, the source doesn't get any better, but the listening experience is, because digital audio recording is one hell of a compromize in comparison to analogue, because if you look at it in a temporal way, less than 1% of the time of rendering, you're actually being given actual signal, the rest is basically fill, extrapolation, smart extrapolation, but extrapolation nonetheless, and in those 99% of virtual audio, a lot of crap is hiding, and this crap is not super evident, but it degenerates the rendering enormously, so even the slightest mitigation, like dithering with added white noise for instance (which is nothing but adding a couple of bits of entropy, which dramatically improves the "digital" transient problem), is a huge improvement, especially for long listening sessions.