Ollie and most definitely Liz and Sam are being drowned out by the other HMs, as there's so much going on with the others.Showing them in the same HL show just reinforces how quiet they really are in there - making them look even more boring.
While there's no expectation of Sam and Liz to be dry humping other HMs or sharing a bath fondling Dappy...there's little they can really do to get screen time, because they've been overpowered and drowned out by the bigger characters in the house, with their arguments and their relationships...There's just not been enough 'room' for Olliee Sam and Liz really.
I think Ollie will win, unless he does something really smutty and lowers himself to the likes of Dappy Lee or Luisa over the coming days, then he's toast, and then Sam will probably win, unfortunately, but that's how it goes on this show.