I understand that logic based on past performance.
But Brown is 26 years old, still relatively young (only 2 years older than Horton). If I were Cubs front office and coaches I'd do everything to develop Brown's pitch repertoire over the winter to be a starter. Then based on spring training results, a decision can be made to move him to relief.
In part Ben has to be committed to being a reliever vs. starter. And feel he has been given every chance to earn a starting job going into 2026. Financially, starters get paid and relievers get the scraps.
Also, his trade value is higher if the Cubs go down the route of adding a 3rd pitch and work on other weaknesses even if he gets squeezed out of the rotation.