I can think of two things:

1) Maybe he was advised that this is a history "high" for selling and to do so has greater long-term value?  Certainly it give Bob greater short-term value.  Songs can't exactly sit in museums like The Louvre.

2) Maybe Jakob doesn't want to spend his time administering that huge and valuable catalogue and also chasing down what are likely to be increased streaming revenues.  Clearly, they did already have someone working the catalogue for licensing and placements so I'm not sure we'll see a huge difference there.