Bitcoin is unique by having many following things: PoW, no premine, decentralized network, no censorship, and decentralized developments so no issue if one Bitcoin developer left like how Satoshi Nakamoto left the community and no longer developed Bitcoin Core years ago.
satoshi NEVER worked on bitcoin core. .. core is a brand that came about by colluding devs in 2014 creating the brand in 2014, long after satoshis disappearance
also one dev of core can leave without causing big effect. but if all the colluding devs messed up or left, then there would be issues as its the sole 'reference client' for upgrades and protocol changes.. thus would affect 99% of everyone should an issue arise. and yes core are centralised once you look at the devs funding background and their colleague/partnership interactions. they do not act as independent devs, but a collective
we should not just cower down and give blind loyalty/obedience to core as gods/governors of bitcoin, even if thats how they act. we should remain vigilant and scrutinise and peer review them to ensure their decisions do not cross the line.
too many people have just let core take control and cross the line many times of whats best for bitcoin, people whom have become defensive loyalists of core devs.. there have even been events including their sponsored actions to enforce their roadmap proceeds as planned, even when the greater bitcoin community have asked for other options
dont fear scrutinising core devs, dont fear peer reviewing them, dont fear criticising them. its the only way to limit how much they get to control
and dont confuse the allowance of core devs whom let smaller coders to bug test, grammar check code/translations via push requests VS the core devs with github force-merge/commit privileges
its like saying a newpaper is open(to read) but to become a newspaper editor is a closed circle of employees, even if the newspaper has a comment section for the public to leave public comment, moderated critique and moderated newsmedia suggestions