I've been thinking about this one recently. Surley for a host that rents servers in an external datacenter, from a customers point of view, it's better that they were a reseller/resold the whole server, but with end user support.

Why?

Because instead of a ticket going:

customer >> to the host who rents >> the datacenter techs >> back to renter >> back to customer,

it would go straight:

customer >> datacenter >> customer

Cuts out two steps, which could represent hours of time?

In theory, if a host/person who wants to become a host, is happy to find a high quality reseller, whom don't oversell, they would in fact be doing their customers a favor. It may cost extra (certainly would when it comes to shared hosting, because on a reseller the biggest problem is normally space IMO), but it might be worth it...

Just a little idea I thought of...

The way I'm interpreting your question: why not outsource your support to the DC if offered?

If that's what you're answering... here's my answer:

Customer service is a huge thing in the web hosting industry. I would say about 60% of web hosts have outsourced their support overseas - leaving out the personal touch in customer service and care. Providing support directly, in-house (within the company as opposed to directly within the DC), the customers have a more personal feel - and the owner of the company can have some direct input on their customers and actually be part of the business with them.

Sure, it would be quicker. As a client though, they would most likely would have no problem waiting a bit longer for a personal reply from a knowledgeable individual that doesn't babble techno, and speak in program Halwanaguilian (made up language).