One issue is getting the different orbital planes covered. Its possible with an "upper stage" booster[0], but that is significantly more expensive than a typical CubeSat carrier/deployer[1] for the ride-along launches. As far as I know, there is no current smallsat/cubesat sized upper stage intended for changing orbital planes.

[0] https://en.wikipedia.org/wiki/Centaur_(rocket_stage)

[1] https://en.wikipedia.org/wiki/NanoRacks_CubeSat_Deployer