7am is not reasonable! Loads of people are still asleep at 7am, or at best hauling themselves into the shower. It's like getting a delivery at 11pm — a good chunk of the population is going to be in bed or close to it
But like every other 'what time is it reasonable to' discussion, people's lives vary and it's simply not possible to find a time to suit everyone, or probably even the majority.
At 7 am, some people will be still in bed.
Some people will be awake but in the shower, getting dressed, feeding babies or in the process of all manner of other tasks where the arrival of a parcel would be an inconvenience.
Some people will have already gone to work (like our DPD worker and all the people who were in the depot sorting the parcels that they have just collected, believe or not, not everyone works Monday to Friday, 9 to 5, with a commute of an hour or so).
Some people will have just gone to bed after being on the night shift.
Leaving probably only a minority in a position to receive a parcel without being inconvenienced. So the parcel people have to get on and deliver their parcels at a time that works for them, the people who are expecting them will do well to designate 'safe place' alternatives if possible and then everything else will have to be dealt with using the dreaded 'we tried to deliver' card.