First, I know it may sound weird, but profit is not always the end goal. Sometimes, especially for businesses in certain industries, such as real estate, they need to generate revenue even at great expense. Remember, during this time they were offering $200 in resort credits and comped rooms for people that have never gambled before. Maybe the decrease in profit is worth the increased metrics.

Second, when the hotels are at basically zero capacity, there's not much increased cost associated with ghost stays, because they have to maintain a minimum number of staff just to operate the property anyway. If they can put everyone in the hotel on the same floor, the number of staff they have to maintain may not exceed the absolute minimum number of staff required.

Third, MGM still got their resort fees for a long time.

Fourth, and probably most importantly, MGM is at its core a gaming company. They cater to gamblers. Their focus on mitigating cheating is cheating by gamblers. It's unlikely that they would have people watching or caring about "ghost" stays to earn hotel status. Their core mindset would be to focus on room shenanigans involving gambling. For example, offers that require a minimum of two midweek nights, come with table play, F&B, etc. - they don't want gamblers booking Wed and Thur night and stopping in Friday morning and taking advantage of all their comps. They likely don't have people in this department that are particularly familiar with Hyatt elite status. As a result, these issues tend to be put aside, even if people in the company know about the issues, and consider them to be issues. Eventually, someone says "ok, I guess it's time to deal with this" and that's when they start.

Just because they made this change now, doesn't mean they *now* think this is a massive problem, and their mindset now is diametrically opposed to their mindset before. The amount that they care about this issue could have remained unchanged for the last year, and they just happened to get around to fixing it now.