That's part of the reason they are using 60 GHz.
A frequency range has a limited bandwidth. Using Shannon theorem, the maximum bandwidth for the 2.4 GHz range is around 30MBps per dB of SNR total. No matter in how much channels you divide the spectrum, you won't be able to beat that. It's either a lot of small bandwidth channels or a few large bandwidth ones.
Passed some point, the only solution to increase the bandwith is to increase the spectrum and that's what they are doing with 5 GHz and now 60 GHz.
Well, there is another solution and it's beamforming. The idea is that instead of broadcasting everywhere, you create a narrow beam just for your target. On a primitive level, that's how antenna dishes work and it improves the signal/noise ratio. This is the idea behind MIMO and similar technologies.