I wonder how you come to that conclusion because from the three Scandinavian monarchies the "powerless" Swedish royals have the lowest approval rates. So the connection you seem to make with the examples of Japan and Sweden: the more powerless, the bigger the popularity, hmmmm....
Popularity is not a function (only) of the "power" the king has, but rather of a series of factors. It is incorrect from a logical point of view to infer that king A is more/less popular than king B because A has more/less executive or legislative powers than B. Accordingly, what I questioned was
not that being powerless makes a king impopular, but rather your argument that a powerless king is "irrelevant".
The King of Sweden, for example, and the Crown Princess for that matter are certainly
not irrelevant IMHO even though they are, by your standards, "powerless". First, they are kept constantly informed of government policy, as mandated BTW by the Swedish constitution. As I said, that happens in official Councils of State, which are held by the King with the government at large every 3 months or so, and in formal meetings of the Council of Foreign Affairs, which is chaired by the King and, under the constitution, must be convened before any major foreign policy decision is taken by the government. In addition, the King frequently meets informally with the prime minister, other cabinet ministers and MPs and, certainly, raises questions of public policy in private with them, fulfilling his mandate to "warn and advise".
Second, Swedish royals are extremely active in representing the country on the international stage, not only by hosting visiting heads of state in formal state visits or going themselves in official state visits overseas, but also by leading several non-official Swedish delegations in business, scientific, or cultural missions abroad.
Third, as part of their "ceremonial" duties, the King and/or other members of the Royal Family recognize the achievements of private citizens (in the form of medals or awards), and support non-governmental organizations, local communities and local businesses, which matters a lot to a lot of people. Besides, when the King delivers his annual Christmas message, or attends a remembrance service or national day celebration, or opens the Swedish parliament (reading BTW
his own speech and not a government legislative program as in Britain or the Netherlands) , he actually serves as a national symbol to whom people pay attention. His words, in that sense, do matter and, without being political or controversial, Carl Gustaf and the Crown Princess actually have both drawn attention to several important social issues over the years, sometimes far more openly than monarchs in other countries who, because of their formal constitutional link with the government, but lack of political responsibility, are required to keep quiet.
Maybe it is just my personal opinion, but I strongly feel that the Swedish (or, for that matter, the Japanese) constitutional model is the way forward in terms of the future of European monarchies and I'm glad to see that Willem-Alexander, who constitutionally still remains a very "powerful" monarch, seems to agree with me. I would only make an exception in particular cases like Belgium or maybe Spain, where national tensions require a somewhat more activist king.
