R18 - She does, however, have enormous influence, which is another form of power.
She also has three constitutional powers: the right to be consulted, to encourage and to warn.
None of her PMs, with whom she meets weekly, have ever had anything but praise for her acuity, and she is privy to the State's most delicate secrets - state documents are sent to her each day no matter where she is for her review. As Head of State, she takes off the government's shoulders the responsibility for hosting high-ranking diplomats and other Heads of State. In short, she has access and a channel for influence that ordinary citizens do not have.
She may not have power, but she's no ordinary citizen, either, and stands apart from the rest of her over-privileged relatives.
As for the cold - kidding aside, they don't call pneumonia "the old man's friend" for nothing, and for her to cancel within 30 minutes of her arrival to an engagement she has kept since 1943 seems to me, er. significant.
Perhaps with the corona virus about they are just being careful and keeping her out of crowded rooms - if we are to believe the tabloids, half a dozen people in the UK have been admitted with possible symptoms of the virus.
It would be quite the irony, though, if Philip, who will be 99 in June, outlasted her.
If he does, the funeral, for Harry and Meghan, will take on a nightmarish quality, indeed, if Philip is the chief mourner rather than HM, who has gone out of her way to be so conciliatory toward them.