I don't think it is necessarily best to rely on the "community" to ensure that each implementation of a bitcoin node is secure/safe to use.

Members of the community might have, at most a few million dollars worth of bitcoin of their own money at stake, but even if they make a mistake, they are unlikely to personally lose any money. On the other hand, there are several bitcoin related businesses that have billions of dollars worth of customer money, and hundreds of millions (and in some cases billions) of dollars of equity who have serious incentives to ensure these types of bugs don't pop up with software in production, and they have incentives to have fail-safes in place to prevent any actual losses if/when these types of bugs make it through the cracks.

I would point out that I am not aware of any major exchange "pausing" deposits and/or withdrawals immidiately after this bug was discovered, however anyone running the relevant software would have taken some time to stop deposits/withdrawals to upgrade their nodes (which would include reviewing the code). This leads me to believe that the majority of exchanges/businesses are running their own custom node software, maybe not exclusively, but this is at least part of what they are running.