The problem is that these achievements are weak in several areas. Together, these weaknesses make them far less attractive than the alternatives.
Each of these achievements only affects a single buff. Despite the gereral nature of the description, there is only one buff that corresponds to each achievement. Minstrel's Aris increases 'Bard group songs that affect combat or casting skills' but it only changes the magical boon line of buffs (end ability is dove song). Bladeturn affects 'songs that increase avoidance skills', but again that only helps the insatiable ardor line (ends in balletic avoidance.) So, in general the return per point is kindof low.
In addition to the above, the returns are a percentage of the current skill. It may be necessary to spend many achievement points before getting any visible increase in the affected skills. This again means that the return per point invested is low.
Other classes can already buff many of these skills better than a troubadour. Self buffs and offensive/defensive abilities for other classes can already increase skill far higher than troubadour can. Eventually, you will reach the point of diminishing returns making each point spent in these lines even less valuable.
Other achievements are just better. Minstrel's Melody will increase the haste buff for bards, but the return per point is far less than taking the stamina line and putting a full eight points into fortissimo. DKTM is still the only end ability worth taking for solo, group and raiding.
All of these points taken together are why these particular achievements are rarely chosen by players. For a solution you either have to change the buff so that the achievement is useful or change the achievement itself. In their current state, I see no reason to choose those achievement lines.