Again. Lagging indicators.
We'll find out in a week or two how successfully states that have relaxed their restrictions are handling things. It was unlikely to be a "restrictions relaxed, 24 hours later there was a 4,000% spike in cases and triple the usual death toll" situation.
Also, comparing non-adjacent states isn't necessarily going to mean much. Florida might have things well in hand. As I noted recently, Indiana's numbers have been basically holding steady for a good month or so, with the (densely populated) county where the ICC is representing 30% of cases despite only having 10-15% of the state's people in it. The adjacent counties add something like another 50% to those stats.
And as has been brought up, the problem is that many people might well pay increasingly substantial penalties for attempts to change or cancel travel bookings. The current hotel registration setup shifts from a $50 fee to 'one night' as of June 8th, as has been discussed. Especially for some of those downtown rooms, that's a substantial bump.
It's the push/pull of things. Vendors and attending companies are going to want to know the likely attendance to quantify the risk/reward potential. Attendees want to know who is showing up to make the same calculus. Gencon seems to be held waiting to see what the city/state are doing, and they (the state/city officials) seem to be content to wait it out. Which is nice for those who still wish to see the convention happen, but also draws out the process of something many view as inevitable.
Hypothetically, IF this does have to cancel, the distinction between them doing it in early June versus early July could be massive, not just in costs to potential attendees, but to vendors trying to shuffle their bookings around, local businesses abruptly having the rug pulled out from under them as they struggled to try to work out how they might safely cover attendees, etc. Edit: not to mention the risk of potential impact to reputation. Fair or not, people will react not just to actions taken/not taken, but the time line in which they were taken.
An event of this size has thousands of moving parts. "Let's just sort it out a couple of weeks beforehand" is not going to see things smoothly come to a halt if necessary. 4 weeks from showtime might seem like a lot, but it's a lot more than just having to figure out what to do with the hotel portal and some people needing to contact their airline of choice.