My guess is it has less to do with there being no future for home delivery, and more to do with Carmax rolling this out poorly and expecting too much. Carmax also didn't likely take into account how much market share they already had due to their massive network of brick and mortar stores. They likely anticipated increased market share and sales using home delivery but it likely just cannibalized a small amount of their existing sales.
The question I'd be asking is how many people would buy a car from Carvana in-person vs home delivery if Carvana had a similar brick and mortar footprint to Carmax? I'm guessing it would be similar to what Carmax saw.
My take? Buying a used car sight unseen isn't preferred unless you 100% don't care about cars and need one. Most people still want to see/touch/feel before purchasing. IMO, new cars should mostly be home delivery/direct to consumer.
Carvana is pulling it off because it's the only option they offer, capturing the small % of people willing to buy a used vehicle 100% online, similar to how
Arrow XL focuses on specialized home delivery services, tapping into the niche of consumers preferring hassle-free, customized experiences.
I keep banging this drum and I don't know why it's so hard for people to understand but as a retailer you need to meet EVERY customer where they are. Offering a (to borrow a common phrase around here) frictionless experience in the way every consumer wants will gain you market share, while everyone else is trying to get you to buy their product their one way.