No, it's because they expected Ethan to walk in and fill FNS's calling style when he had just spent the past year with Boostio's, and the optic core had spent the last ~3 with FNS's. The mid-year switch and remaining as a coach are important so the style doesn't change, and the IGL is still there every timeout.
Edit: also, Haodong had been with the core for years. So maybe FNS/Boostio are not good candidates, but Boaster is. No wait, they just moved players around this year 🤔 okay maybe this is even more edge case than I thought.