Skilled TV producers and editors can fit more than one storyline into a 1 hour episode. I know some people love showmances and we can still have them, along with other storylines for variety. We can see from the live streams that housemates are absolutely talking about other things in the house.
A big criticism I have of the daily shows is that production seems to only have the resources and/or talent to be able to include one storyline per episode, and it’s usually Colin and Holly.
In fact, there really has been only 1 storyline this entire season - Holly and Colin. It’s growing old even with the showmance lovers and shows a lack of creativity and motivation to do anything else.
Even the Channel 7 era episodes had more than one storyline going at a time - however they also had weeks to months to edit the footage, so maybe the team at Endemol Shine just don’t have the ability to do good edit work with 24 hour turnaround.
Previous seasons of BBAU had multiple showmances going at the same time. However the 30 minute episodes still managed to follow other storylines to give variety for the viewers who aren’t interested in that.