Abolishing the monarchy would involve rewriting the constitution - if that was happening every province would want to slip in their own terms - Quebec would want specific French language rights and autonomy and if Quebec got their way Alberta would want something similar. We successfully altered the constitution back in 1982 - it took 2 years and the country almost blew up over it.
Basically it would be a total shit show. Considering the impact the monarchy has on our day to day life (basically zero) it’s easier to just let sleeping dogs lie
Or if you are on a Boeing plane and a side panel/door spontaneously flies off off you don’t get sucked out
/s, but not really /s