The anorexia comparison is difficult to make because the diagnostic parameters for eating disorders have expanded a lot over the past few decades. A diagnosis of anorexia used to require a BMI below (I think but may be misremembering) 14 but now you can make a diagnosis of restrictive eating disorder without recourse to BMI or weight.
It's also difficult because anorexics try to hide their disease or even admit it exists so there may be many with such an ED who have not been formally diagnosed or showing up in stats. Same with bulimia / BD. Where people with body dysmophia seem to be very keen to seek a formal diagnosis asap to get access to drugs / surgery.
However I think it would be very fair to say on an anecdotal level that body dysmorphia has overtaken anorexia / bulimia / restriction as the socially contagious mental health condition du jour and this is certainly the case in my experience.