It is about the movie industry, but in some cases this could also be true for video games in some kind.
But video games are a little bit different. No cinema, no need for a TV. The kind of games are also different on smartphones, consoles and PC, I guess.
E.g. Point and Adventures are best on the PC, on the Smartphone and Tablet maybe more like hidden object or match 3 games. And on consoles, Platformers, Beat'm'Ups and so on.
Also the problem with "Indie" is, what you need is the marketing in some form. And if you do it yourself, you have not the time, to create your games.
And if you let do it others, maybe it is like you would have a publisher.
Or you are not anymore a single developer, doing all the things alone. Maybe it is like in the music industry, are you playing the guitar and singing and self-promote yourself, or do you have a band and a manager.
No matter how you want to do it, you could not hide from everybody. And you have to publish someday. It is like an exibition, if you are a photographer.
Also the scope for your first projects are important. Maybe at first, you are looking for games, that only would take you 3 hours in the core mechanic. You could add some more details, and soon as you look around, you are sitting 3 days on your project and it grows.
After two weeks, you may have something, that is worth showing to the public.
You also could think about special niche, like lerning apps for kids, or games for the government. In some countries it is also possible to get some funding for your idea.
In Germany e.g.
https://www.fff-bayern.de/de/foerderung/foerderbereiche.html
Or games.de
https://www.game.de/games-foerderung/
You could also try, to send your game to a contest. But sometimes, you lose some publishing rights with that also.
Microsoft, Intel, Amazon, or Epic Games do sometimes contests. And you also could try, to get an award like
https://deutscher-computerspielpreis.de/
Example from Microsoft, 2014
https://imaginecup.microsoft.com/de-de/Competition/1001
Intel with AppUp Store Contest 2012
https://www.codeproject.com/Competitions/598/The-Windows-8-Ultrabook-App-Innovation-Contest.aspx
And there are some more stores you could publish, like nVidia Shield TV Store, Amazon FireTV Store, AndroidTV Store
Not every game has to be in the Google Playstore
https://indiegamesshowcase.withgoogle.com/europe/#winners
But finishing your game would be the first step. You could have Twitter or Discord and post some progress, to build a little community around your work, because often these contests are depending on votings from your community.
http://contest.gamedevfort.com/
But some contests also want you to use there specific engine or assets or something like that. Or publish in there store.
You said, that you published something on itch.io, maybe something like that could be your next step.
https://itch.io/jam/igmc2018
But I don't know, what about the publishing rights, if you could give up on some royalties or so.
You could also decide, to try the ludumdare JAM, if your idea and content may fit to the theme of the Ludum Dare contest. In a JAM you could also use code from before and assets and so on. So you are not tide to strict rules.
https://ldjam.com/
Also in some bigger cities often are some game jams, where you could show your games. Or have a meeting with some publisher. At the gamescom in Cologne e.g. is also an Indie Booth.
https://www.gameswirtschaft.de/gamescom/indie-arena-booth-2019-volunteers/
But that is more public, and I guess, a game would need some waight to it. Some special idea, some unique graphic style, some fun mechanic and so on.
You also could think about Steam Early Access, or creating something in your game for Twitch. Some "random" stuff. So that your game would be a content creation tool for the Twitchers and YouTubers.
If you look at your game as ART, the publishing posibilities are nearly the same as in photgraphs and or movies or other art forms like dancing, music, sculting and so on.
So is it possible, to make a living out of it? Yes. But it depends, what kind your game is and what your target audience is. For point and click Adventure Games e.g. there are special boards, where you could get intouch with the moderators and they would help you promoting your game.
https://www.adventure-treff.de/
Also, if you want to create a game for the OUYA, there some people, who are interested in new games for the OUYA. Also some YouTubers show off the niche games.
You could also decide, to make somethink like a Raspberry Pi "exclusive" game. And your game would be tide up with the Raspberry Pi or something like that.
I guess, at first, you have to focus on your own idea. And in the next step, you could watch out, if in your country, town, near you, are some conventions or maybe also some store owners, who want to have a game on there website for a promotion.
App Game Kit can do also Web-HTML5-games. You also could decide, to create a tiny tutorial app like a video help for something special. AppGameKit can playback video on Android. So depends, where your focus is.
AR, VR, Touch, Networking, Browser, 2D, 2.5D, 3D, you are not limited by App Game Kit.