"As O2 is being bought by Three"
O2 (well, O2 UK) isn't being bought by Three until it's been approved by regulators (in progress - brown envelopes pending).
"..an industry which has thrown away One2One, Cellnet and amazingly Orange (BT should resuscitate it),"
Since Orange (nee France Telecom) own the Orange brand I suspect BT would be stuck licensing it from them if they wanted to do that. At least they would own the EE brand outright (providing their lawyers are on the ball and they wanted to continue using it).
Anyway the Orange that was crushed out of existence a few years ago had nowhere near the goodwill attached to it that the Orange of Hans Snook back in the late 1990s did.