I am not sure this is glitches or intentional.
I am playing in career hard mode with MKS and I am able to mine ExoticMinerals on kerbin and recover it to sell it. Each unit wroth 160 and a 5m Kontainer wroth more than 10M. With support by planetary logistics and a remote mining base, I can even just launch a empty Kontainer with logistics module and recover it instantly.
It sound like we should not able to mine on kerbin (may be the land is not own by space program?). It should be ok on other body since the transport effort and cost is not cheap
A similar case is each unit of ResourceLode cost 250, than a small one worth 1.25M and a big one worth 125M, although it take effort to take back to kerbin, but this is way too much.