I don't know about most competitive but where I did my Master's (UK), everybody on the PhD programme seemed to be either a Medievalist or a Modernist. But rather than feeling delighted that fewer people were in my subfield (British C19 novel) my fellow Romanticists/Victorianists and I just developed a complex about how English departments love to fund Medievalists because they feel like all of the language-learning gives the subject a kind of academic weight which just reading lots of lovely novels apparently lacks... i.e. a hangover from the invention of English as an academic subject at the start of the C20. This is probably rubbish (if true, why do they also let in a bajillion people to study Virginia Woolf?!) but I definitely felt that the Victorians were a lesser-funded subfield. And in the UK, funding is what really matters: it is relatively easy to be admitted to programmes but funding is extremely scarce and it is this which generally decides whether the PhD is actually a realistic prospect or not. Anyway not sure how relevant this is to the US system (into which I am blindly attempting to launch myself) but just my two cents!