Well we are also not other countries. We have different culture, socio economic makeup, different population distribution, and different history. Something that works in another country isn’t guaranteed to work here.
I think a key reason why nothing will ever change is because moderates offer “hey we can do mental health checks, bans on ownership for people convicted of violent crimes, and mandatory wait times” to meet in the middle and compromise but both sides don’t want to do that.
Just a symptom of how polarized the nation is. Until we fix that, nothing will ever change.