Lou becomes just the second to this mark and it's not as if there's going to be a rush of players joining them, at least not for a while.
You'd have to think Beck gets there, but then I'm not sure any others on that list do until Ott and Foxx, but that probably won't be until next decade.
Babe is definitely slowing down and I reckon a year or two might see him out. I expect this season's recalc to be fairly cruel to the big guy but still hold out hope of him mashing 600. It'll be a close-run thing as to whether or not Lou catches him.