There are a fair number of things that many people are probably OK with giving some general parameters and approving a purchase and have someone else take care of all the logistical details.

The bigger issue is that I'm not really willing to pay someone what it costs to e.g. take my car in for state inspection, run my errands, etc. I do have some services for things like getting my lawn cut but it's harder/more expensive to get someone to handle unscheduled one-off things.