Its an interesting phenomenon - when I shared this same review with our homebrew club, an ex-pat member had exactly the same response as you. I'm sure it is better fresh, just as having any cask, fresh version of a beer is good - try a fresh, cask version of an IPA and then compare it to a bottled version. The hop character, aroma and flavor will be significantly different.
But, I'm not willing to say that bottled IPA is carp - that would be wrong. And just because I'm not in the UK drinking a cask version of a bitter, I'm not willing to say that no good bitter can be found, which isn't what you were saying, of course. What you were saying is that the cask version is different, which I'm sure is true. My homebrew club friend was saying that any bottled bitter available here is carp, which is ridiculous.