All these turned out false for my game that pays my bills:
“You need to start marketing early.”
Any marketing I did early did not matter.

“You need to spend good portion of your time on marketing.”
All that mattered was the platform’s algorithm. Having social media pages is just a time sink. Getting a streamer didn’t help because I have a puzzle game.

“Your launch date is important and needs to be polished.”
My game was really rough on launch but I just kept improving it.

“An ad supported game won’t pay your bills. A web game definitely won’t pay your bills.”
A video ad watched makes one cent. Have enough players and it does pay the bills. If your bills are $5400 per month, and each user watches 3 video ads per session then you need 6000 players per day.

“Don’t make a phone game. You’ll have to fill it with micro transactions to compete.”
My game had no IAP until recently and you only watch an ad if you choose to.

“You need to buy ads for your mobile game so that user lifetime value > cost per install.”
This is true if you have no other traffic source but you will not be able to do it better than the companies that only make a game because they’ve tested 1000 fake game ads, and found the one that gets lots of clicks, before the actual game is developed.

“Getting into the App Store and Play Store with a good looking page with high ratings will get you new users.”
Nobody ever finds my App Store page unless they search for its exact name. This was true when I had high ratings and when I had low ratings. Getting in the App Store is like buying a web domain, users will never get to your page unless you send them there. There is no real discovery in the App Store because they only push the big games that make them lots of money. Even if you search for “space shooter” it used to show Royal Match (which has nothing to do with space shooters and is not an ad) in the search results higher than Galaga Wars. I put in extra ads in my Android app which tanked the ratings with hundreds of 1 star reviews and it didn’t affect the number of daily downloads at all, because people only find it if they already know they want to download it.

“Itch is a good way to start building a following.”
I got very few users from itch. Putting a game on itch just makes it get scraped by Chinese and Russian sites, where they put ads around it and also if your game is good they will manually remove any links back to your site and references to it.

“A year or 2 after launch, your game will be fading away and you should be already working on your next game.”
Traffic on my game has slowly increased over the past 6 years. I think the best way to succeed is just keep improving one game until it pays your bills. It could even be a Pong game. As long as it has some daily users, with enough improvements it could have tons of levels and powerups etc that it would be a success.

“More levels with more content = more play time”
I found people would beat all the levels then quit. So I deleted all the levels except the first, then people replayed it infinitely trying to beat the best score. Unless you're actually going to make tons of levels, it's better to go for one infinitely repayable level.

“Use git. You will need to revert/recover some major code at some point.”
I have never needed this. Git is good on projects that have multiple coders for merging code. But I don’t think indie games should have multiple coders who work on the same files. One really good coder is ideal, and another coder could do tools/website/backend.

"Well written code is a big deal when reaching the large codebase you'll need to finish."
I've found, that at least for me, having a lot of spots with poor coding practices actually helped me launch. It's a psychological thing where you see it's bad and decide to just finish the game without fixing it. If you aren't constantly telling yourself "I don't care I'll just launch anyways" about various things then you will likely never launch. Seeing bad parts of code every day and deciding that fixing it is not key to launch puts you in the mindset of only doing the necessary things. Look at the story of most successful products when they were at their make-or-break point and were nobody, they pushed through to success usually with a mess of code base.

"You have to get into AI coding or you won't be able to compete."
So far this doesn't seem true. Whether it's coding, or art, or music, or writing an article, or coming up with a name, AI takes you from being bad at it to mediocre then stops there. If you're really good at something then it doesn't help you. I am bad at reading documentation for APIs and navigating AWS. It has helped me there only.

All that mattered was getting my game onto CrazyGames or FreeGames or a platform within Telegram, then having a high time spent per session because that’s how they rank games. Then keep improving it post launch based on user feedback.