One of my father's most significant accomplishments was being part of the team that brought the metric system to Canada. He worked hard on the project. He also worked very effectively—it is a fait accompli. All that said, it was mistake. It accomplished nothing useful. For science, metric is a good thing but most of us aren't scientists and don't do science. Scientists were already using metric and were effectively bilingual in measurement; the rest of us didn't need to be yoked with this. It was just a pointless exercise in rationalism.
It also had costs. Switching to a different system of measurement units than your largest trading partner was to shoot ourselves in the foot. Especially so given that our largest trading partner has an economy ten times the size of our own. We pay a price for this—it's a hidden price but it's real nevertheless. It also had the unfortunate effect of cutting off from our own culture. Imperial measurements were a huge part of our history. We still use the expressions but it connects to nothing.
Could it be reversed? Yes. And it would be ridiculously easy. We could just let it happen. It would be to our interest. Not everything would come back exactly as it was. At this point, it would be easier and advantageous to simply adopt the slightly smaller American gallon than to resume the old Imperial gallon.
Just to say that, however, is to brush up against the underlying problem that makes what would be culturally better and easier to do politically impossible. For our political elite, "Canada" is a negatively defined country. They have eliminated everything that was actually particular about the country and replaced it with a reflexive anti-Americanism. That was the real point of going metric—it was an attempt to foster a connection with a European culture and economy whose only appeal was that it was not American. That hasn't worked out very well. Europe is actively committing cultural suicide a I write this.
We might not be able to return to what was and, "foundations once destroyed, what can just men do?". All that acknowledged, tt still makes sense to "stand athwart history yelling Stop" even if the magazine founded on that principle has itself largely surrendered.