In particular in the US there are more guns than people. Attempting to confiscate all those guns would inevitably fail and likely lead to massive civil unrest. It would also fail to prevent criminals from still having access to guns.
Perhaps an arms-race is unfortunate but unilateral disarmament on one side is not a practical solution to the problem.
FWIW the US is not the only country where citizens are allowed to have guns. Look at Switzerland for an example.
Relative to the USA status quo, Swiss gun laws are like a far left socialist wet dream. No electable left-wing politician would ever imagine being able to get one tenth of Swiss-style laws passed in the USA.
The debate is never “guns or no guns”. The government and its agents always have guns, even in places like Japan. The debate is whether or not the unwashed masses also are permitted the right to defend themselves alongside (and sometimes against) the agents of the state.
History shows us quite plainly the dangerous issues with the circumstance where only the state is armed and civilians are not, from the holocaust all the way down to the 2004 Republican National Convention in NYC.