It's because while IT and automation matters, it's not the only thing that matters. The most important thing a CEO can do, especially in this industry, is set culture. That's their greatest role. Culture is far more important than IT.
Herb's positive legacy in this industry is well deserved. This is because Herb set the culture at Southwest, and it's well known that Southwest's employee culture has been--under Herb's leadership--its greatest asset. Herb set it in past crises, such as when they had to sell their fourth airplane to keep the airline afloat, and Herb got the employees to band together to create the 10 minute turn, which allowed them to effectively fly a four plane route network with three planes.
This "band together" culture has saved Southwest's skin countless times. It's what has let them run a highly complex route network of mid-market point to points (vs. hub and spoke) with inferior technology, and yet with good service and competitive reliability.
The problem this time around is that Southwest suffers from the same labor shortage as all other airlines in the industry, and it's this labor shortage that led to their other deficiencies from biting them in the ass. Unfortunately, culture can't solve a crisis when there simply aren't enough people to "band together."
Southwest's IT issues are very well known in the industry, and reports are the current CEO and COO understand and aim to address. This week emphasizes the need, and we can expect SW to embark on a modernization plan. Just remember though, IT modernization takes an enormous amount of time. While we wait the better part of a decade for better scheduling and reservation systems (SW's maintenance system modernization is years and years in and is still ongoing,) SW's current CEO can best spend his time in the trenches of the operation preserving and strengthening culture.