The 7/7 inquest and radios

I've been keeping a weather eye on the inquest, and was surprised to hear about the radio communication troubles.

I'm surprised, because as far back as the Moorgate disaster http://en.wikipedia.org/wiki/Moorgate_tube_crash 35 years ago, the authorities knew there were issues. The Kings Cross fire http://en.wikipedia.org/wiki/King's_Cross_fire 12 years later had similar problems.

Why after so many deaths and reports into these issues was nothing achieved?