Tsegay has great influence over the pace of pacers and wavelights, and gets to dictate a fast aggreesive early pace, for many reasons.
She normally has the fastest personal best time in the field and is fit and in shape.
She is the current world record holder in the 1500 and a former record holder 5k record holder. She has run numerous top 10 times at many distances.
She has multiple global championships and medals.
She is arguably the biggest star in most races.
She wins paced races that start very fast and aggressive more often than not.
Her aggressive style of running makes for more interesting and entertaining races than those that start out slow. The possibility of a new world record makes a developing race more interesting than if the race went out more slowly. Her races are often promoted in advance as world record attempts and that adds interest.
She almost always starts races fast and stays with pacers out at very fast paces, so she backs up decisions to have a fast early pace.
Even when she fades and loses the race, the race is arguably more interesting than races that start out slow.
A fast early pace helps ensure that there will be many season and personal bests run by other runners in that race. Eleven women broke 4 min in the Silesia race. Meet promoters and many runners like fast races.
Chebet, Hunter Bell, Hiltz and others would have all preferred that 1500 to be paced much slower than it was. Until they run as fast as Tsegay and consistently beat her she will have more influence on pacing.