There's no motivation for them to get certain individuals more air time other than viewing figures
I agree with this. It's not like they sit and say "ok everyone should get an equal crack at air time, to stand a chance of winning". Basically they show what they think will get the most viewers and the most attention. Which is what their job is.
Watching Sam/Frankie/Ellie/Charlie gazing lovingly into each other's eyes and conversing quietly isn't exactly a ratings winner, and people would soon be shouting it was boring as hell.
Watching Laura get her arse in her hands again, or Ellie hurling abuse at Georgia, or building up the tension to see if Alex will be eventually picked, is always going to get more viewers than quiet smooching on the day bed.