How Would You Prevent/Discourage a Hard Fork

Just thinking about all the hard-forking in the BTC space and thinking about Cardano dynamics. Presumably, the governance process would defend against a fork, and even decide to “fork everyone” if technically necessary through the governance process.

Is there anything beyond the technical aspect of chain voting and governance processes? Is there an implicit agreement with a specific treasury and its governance when you hold ADA on Cardano SL?

Is it correct to say that side-chain governance is always a separate and independent matter?