Sometimes, I dream of developing for Steem but it's been a long time since I last wrote any line of code, which scares me and holds me back from trying. 🥲

I get that. I haven't programmed on a daily basis since the 1990s, and everything is very different now. But, you can start off by making something simple for yourself and build from there.

If the stats you shared are true then definitely it's not a centralized platform but is there any proof to handle this objection more confidently?

Well, we can be fairly confident that their on-chain dominance is less than 10%. If you look at the return-proposal voting from SteemWorld, we see that they have 41.6 million STEEM voting.

Since the overall supply is 462 million, that's roughly 9%. The big unknown is how much they have on the exchanges. I think I remember reading at the time of the Tron purchase that Justin Sun had purchased about 60 million STEEM, so my guesses were roughly based on estimates of 60 and 80 million. But no, I don't know any way to document that. It could be very wrong.

If someone wanted to spend some time digging into it, I suppose you could put boundaries around it by looking at other big accounts, the amount that was pilfered from Steemit wallets on the Hive chain during the Hive fork, and the inflation amounts during the last 4 years, but it would take a while.