because they can't yet. It's a daylight savings glitch, it opens early but is way too expensive and won't actually let anyone join, it will slowly go down for the next hour, people will join when it's under 400
The daylight savings time glitch (which randomize has not fixed yet) will have it so it doesn't allow anybody to join until about 5:40 EST. It'll start at Diamond and go down from there then.