I have 5 or so characters that I've got Learning skills upto the SOCT IV standard. On two of them, it's 5's across the board. That's about ~150 days each on 2 of my characters, and 60ish on 4 of them. In terms of opportunity cost them, this adds up to approximately 20M SP of training ( 2x 5.5M, 3 x 3M).
They should issue this as 'training credit' - rather like the plex cards, and allow it to be traded on the market. Each one consumed credits that many training points to the current character. Do them in units of 1000, and allow overspill (i.e. if you over-credit HAC III, it spills over to HACIV). There will be a finite amount of these in circulations, and as they effectively represent lost time, they will be traded like mad.