Loosing one’s citizenship of birth is a big deal, especially if the new country of citizenship has not been acquired in the course of regular or desired immigration, but merely due to circumstance and under duress.
Canadian citizenship usually is easy to acquire, provided there is proof of employment (at least this was the case forty years ago when we arrived) or maybe a sponsor – some sort of relative who lives here already. Dual citizenship used to be more difficult. Many larger European countries removed birth citizenship from any of their citizens once they assumed Canadian. Of course, Canada does not care much about dual, but it is the country of birth that controls it – either keep it or loose it.
In between there were multiple citizenship and immigration reforms, one of them allowing dual citizenship under the following circumstances: At the time when applying for the Canadian one must prove that there is still a bind with the home country, family or property or other. In my case, my entire family never left their country, they are all in Europe, only myself and at that time my little son were in Canada.
Unfortunately, all this happening before the European Union (EU) came into being.
Also in between and many years ago my son – who has dual citizenship because he was born in a smaller European country – returned to his home country for good.  Meanwhile I am still in Canada, still only Canadian citizenship, and when travelling to my home country am forced to go to the Foreigners’ Office to buy myself an extension for stay, else stay is limited to three months.
To argue: why do those who do not care about Canadian citizenship – because they neither live here anymore nor are interested in Canadian affairs – still keep and retain dual citizenship including Canadian, while at the same time those who decided to immigrate to Canada retain theirs, although they never even visit their home country anymore.
We should allow dual citizenship for those Canadians who are longtime taxpayers in this country and receive pensions in this country, but have all of their family residing in Europe. This not also because of complicated taxation issues arising out of income in both countries, but mainly to make a long term visit to their families, instead of only a measly three months.