I think it's just a matter of time before we see more SB and JR. It just takes time to train these players.
Looking at the coefficients, I disagree with you here. For a 7'6'' trainee trained by a level 5 coach in Shot Blocking (C) gets 0.79 of SB per week as well as 0.23 of ID and 0.11 of RB. Also, for a 6'0'' trained again by a level 5 coach in Outside Shooting (SG) gets 0.62 of JR per week as well as 0.21 JS, 0.08 DR and 0.07 HA so I don't think it's a case of training too slowly, I think it's a case of people not willing to try these tactics out or unaware of the decrease in salary the update has given to these skills.