Yes - I think that you will find that flight times are driven by 2 factors:
1) What the premium market (J and F) want
2) Slots at LHR (as everything cannot leave at 10pm and arrive at 6am).
If Y were important then the MCO-LGW run would be a day flight back from the USA- it would be possible - just - but thats not what drives things......
FD.