They're not allowed to, that's the point. They're stuck in Martinez's rigid possession based philosophy, with a slow tempo building from the back.
That's why people are calling for him to go, as he's by far and away the biggest barrier to us performing well right now. I'd have thought he'd have realised what was going on and adjusted, like Rodgers did with Liverpool annoyingly, but he's so painfully limited as a manager that he has a one track mind and, regardless of whether it's working or not, he's going to do the same thing over and over and over again.
There's a £28m striker there just screaming to be played with two wingers and an attacking midfielder behind him, with the wingers supplying and providing protection for the full backs bombing on, playing more direct football. The pace excuse has gone now as we have Mirallas and Lennon, and Atsu is no slouch. But he's playing three defensive midfielders to sure up the back while we pass it sideways across defence!
It's like he's doing it on purpose to annoy people. With Moyes, he was tactically limited and didn't make the big calls in the big games, but he always knew how to adjust in a slump to make sure we didn't go anywhere near danger. Martinez has absolutely none of that ability.