We share your concerns.
A couple of points about delays though.
It is company policy that we tell you the truth about the cause of the delays. At LHR airfield congestion, ATC slot delays, baggage having to be offloaded due passenger not appearing at gate, etc, etc, continually cause delays. We know that punctuality is at the top of regular travellers wish lists. For that reason it it high on our list of priorities.
It would be my guess that less than 10% of delays into or out of LHR are due to causes that we can control.
We have to endure these problems day in day out and up to four times a day.