None of those systems are interference free in practice, the amount of which increases with the number of users. Spectrum is still scarce but these methods may make it more efficient to use, especially if channel use is coordinated.
Also beamforming doesn't work as well from the mobile station because you don't have multiple, sufficiently separated antennas.
> beamforming doesn't work as well from the mobile station
Beamforming gives roughly the same advantage to TX and RX. While I'm sure mobile stations will eventually take advantage of it for power conservation purposes, very large advantages still stand to be gained even from a one-sided implementation at the base stations which can have multiple sufficiently separated antennas.
Radio astronomy provides a very good example of this: from Earth, stars look like point radiators, yet VLBI astronomy still yields an insanely powerful RX advantage once you get up to effective apertures the size of Earth.
Also beamforming doesn't work as well from the mobile station because you don't have multiple, sufficiently separated antennas.