

No, they do – it’s just not a codified constitution like almost all other countries have.
Proponents of the idea believe that a constitution that has evolved bit by bit over a long period of time and across a bunch of different charters and unwritten agreements/customs is stronger that one that’s done all in one shot. You’ll see the unflattering metaphor that “a tree is stronger than a weed”, which seems a bit unfair but it’s reasonable point – if not one that’s beyond argument or anything.
Commonwealth countries are politically conservative, small “c” and not big “C”, as the general attitude is “if it ain’t broke don’t fix it, even if it’s objectively kind of stupid”. There was a good reason for every one of the decisions that led to today, don’t &^%$ with it, just in case.
For Ontario readers, Farm Boy’s store brand cereals are made in Canada.