570-580? Dream on. 496.
Ironically for a realistic kill rate, about 496. Of course it's doable in blues, but you would be killing things very slowly.
Realistically to get into a pug run that does not have a high probability of failing, you'll want to expect 520+ gear at minimum from people. Keep in mind ease of gearing over time not only means more casuals staying, more gearing, and more pug runs, it actually further increases pugs.
Let's face it. Some bosses may be too challenging for an average pug group, but at least having more accessible gear (read: more 520+ geared players) around means that you can at least outgear the early bosses pretty reliably. That makes for better pugging, to this day now I refuse to join pugs because of the high probability I spend 3-4 hours just to kill Jin'rokh.
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As I mentioned many times, less alts in the playerbase also means less things for non-raiders and non-Heroic raiders to do on their main. Most raiding mains, N or H, will not contribute shit to the trade groups/etc. due to this thing called "lockout," so players in guilds (even 2/12 normal guilds) will only be able to contribute, realistically, on alts. Erase the alts, erase the pug/alt runs.