not really... batching a bunch of orders and delivering them out of a van is about as efficient as last mile logistics can get.
ubereats/GrubHub is a notable exception, since people expect much stronger latency guarantees for this use case.
It's definitely more efficient than driving yourself, but it's also hiring out your driving to someone else, which counts against someone being able to "walk everywhere" because it requires you to assume that the person can make up any shortcomings in their location with mail order. Point is, you can't realistically walk everywhere in most places.
We do not order delivery.
I do not commute currently, but I have walked for 75minutes one way(2.5hours total for 12.5hours a week) for about a year at a previous position with a poor bike route.
We do order stuff from Amazon. Which covers things that are hard to find close by.
There's no way that everyone is lazy in my area. They could definitely stop 3minute drives to the park though.
Do you commute to work by walking? How long does that take you each day? How about the grocery store? How many people do you have to do grocery shopping for? What about buying clothing or other necessities? If you're ordering most of your stuff in, you're not reducing the need for driving, you're paying someone else to drive for you.
No, people aren't just lazy. Most people don't have the time or money to live that lifestyle.