Also, those "mysterious coders" mean nothing if the users don't run their code.
It was the users who used a User Activated Soft Fork (UASF) in 2017 to push through the SegWit update. [1]
The bitcoin network is open and decentralized, and there are several clients and several versions of those clients. [2][3]
[1] see https://bitcoinmagazine.com/culture/bitcoin-independence-day...
[2] See the right bottom under "top node versions": https://bitcoin.clarkmoody.com/dashboard/
[3] the most popular alternative client is Knots. See also: https://bitcoin.org/en/wallets/desktop/windows/bitcoinknots/