IBM 7,000 tape capacity?
I'm not sure where that info has come from, but certainly an IBM tape library (3584/TS3500) that can be used with Mainframe and LTO/3592 media does not stop at 7,000 slots. An S54 frame fits 1,000 3592 tapes or 1,320 LTO tapes. Last I checked you could fit on at least 14 expansion frames of this giving 14300 to 18780 approx, maybe more. That's a tad more than 7,000 or 10,000.