No- Further Long haul will continue to seek (buy) access to Heathrow for the foreseeable future in a very managed way.
Heathrow will continue to lose short haul frequencies and the results will be decline in % of transfer traffic however with an up side for airline yields- particularly for IAG and leading *A carriers as terminators are far greater than those from transfer/transit tickets.
Typically the short haul sector books a loss on transfer traffic particularly in the back of the bus so to speak.