EDITED because my original post was a pure personal attack
You're asking if a place exists for indie game devs to discuss game development, on a forum which exists for that very purpose. The thing you're proposing already very much exists, though not in the exact shape of GDC, because having a physical conference is already unreasonably expensive for the professionals.
It seems like this is really all about you having a political axe to grind, and not about actual game development.
I am being quite genuine; I haven't even mentioned anything else in this post that involves politics in the rest of this topic aside from the one that started it. I used to watch the GDC for specific topics in game development, such as the approach to game emulation where most of the professional industry views at the topic as piracy (Nintendo, Sony, I don't think Microsoft cares, Sega defiantly stopped caring after the Sega Genesis and Sega Dreamcast as Piracy and Homebrew are giving new life TO those consoles to a point were we have new Dreamcast Games) and how it could be turned around to be used as not only another profit margin, but to stop players from pursuing this 'legally' gray area and buy the game legitimately, especially since Nintendo started doing the EXACT same thing selling the game's on the Virtual Console line and calling it the right way while shamming everyone else much like it seems like you are trying to shame me right now.
Which, the talk was actually a good arguement; I'll link it here.
https://www.gdcvault.com/play/1023470/-It-s-Just-Emulation
Next, I get that this forum already accomplishes this; but we could also argue this for anime, horror, movies and so on that already accomplish this and there are conferences that already discuss these topic's, outside the forum to other forums and even social media platforms, some fan panels while others are from professionals in the industry that come out to these to discuss either personal projects or where something is going; Such as the creator of Robotech coming to the USA over to Ohayocon to discuss the future of his Anime, competing against Gundam and the literal hell hole of a nightmare with Harmony Gold has left his creation and after from odd years and discussing it to fans on how to save his franchise from that hellhole.
Which brings me now, in a sense. I look at the GDC, I discover a few topics were not focused on game development, but a political angle in a lot of the panels and a literal section of time for developers to go out and scream in front of the hall. This is technically a free market, I went looking to see if there was an another conference that didn't touch on these topics since aside from Gen Con in the Tabletop scene as an example, there's also River City con, Origin and the GAMA Expo, the latter of which accomplishes what GDC did; but their entire conference is fenced in with a membership buy-in.
So, I do some googling; and there isn't really much else out there to be a free market in, for the USA to an extent, especially FOR Indies; there's the Indie game Utsav over in India and a few others that do 'VIRTUAL' conferences, though they have been more showcase's of other indie development project's than discussions and that's about as much as I could look for, there is even a conference for Cellphone Games which has been a rough mix between Showcase and Conference.
So, in short, I am genuinely asking if there is another alternative that does what the GDC does, especially for Indie and cuts back on the showcase's and becomes less of a expensive commercial you could attend in real life; no political axe to grind, no nefarious plot, nothing. Even more than likely willing to go through with the painful process of setting one up.
