Core is largely maintained by salaried developers, people that work on it for a paycheck, not because they love it or even "get it". They are recruited and operationalized.

These salaries are paid by a few NGOs, Spiral and Chaincode notably, others perhaps even some undisclosed.

These are front organizations for well financed interests, like banks, intelligence agencies, private equity, and so on.

Bitcoin Core is to Bitcoin as the World Health Organization is to health.