Apart from the historical irony - and the fact that a tea-party in England tends to include cucumber sandwiches - Massie underlines the main reason why:
The establishment party controls who is put on the ballot even in the so-called open primaries and, generally speaking, the party isn't going to risk putting forward for selection the British equivalents of O'Donnell or Rand Paul. Genuinely open primaries could change that and that's why no party, I think, has any desire to emulate the openess of the American system. Sometimes, you see, the "wrong" people win. For all David Cameron's talk of a new, more open kind of party politics the truth is, that for understandable reasons (from the leadership's perspective that is), it's only a degree more open than previous methods of selecting candidates.
I know that the Tory leadership has been particularly worried about the influence of small groups of Christianists potentially hijacking local nominations. But their numbers are mercifully minuscule compared to the US - which is why the British Conservatives have been able to tackle public spending directly without the baggage of religious dogmatism.