I'm not sure what you mean by madness here - it makes sense to centralise as much as possible at LHR
, especially with regards to maintenance, connections, etc. There is also the point regarding employment contracts - most (if not all) of the LGW
-based staff are employed under a different contract to the LHR
ones - this has been discussed here before a few times.
Also, as FLVILLA said above, the vast majority of traffic exists at LHR
, and as a result the highest amount of capacity exists there to handle this.