How to minimize phone orders for an online store

In modern online stores there are two basic ways of ordering: the actual online order, when a person selects the product himself, compares prices, fills in the information for ordering and payment. The second person searches for a phone number (as a rule, they try to place it in the upper corner), calls, loads the manager with questions and orders.

I have an online store, and, probably, in the upper paragraph, I understand my attitude to each type of order)

So the problem.

Each online store (for short IM) should work as a supermarket - the buyer interacts only with the system and personnel contacts are minimized. In ordinary supermarkets, we contact only by transferring payment at the checkout, well, sometimes, trying to find a price, for example. This is a miss of the attendants.

The IM format allows you to create almost perfect conditions for choosing a product and making a purchase. I see a few key points that need to be followed in the mechanism of MI:

1. Photos of the goods, preferably from several angles. And the ability to view a large image (for example, about 600 px on the big side)
2. Product options (color, size)
3. The price of goods in national currency
4. Information about the availability of stock (the usual icon, we have a green square) or, if the goods in a remote warehouse - the approximate date of delivery.
5. Convenient and noticeable button "Add to cart"

As for the basket, in my opinion, there must be mandatory elements:

1. Product Name (with thumbnails)
2. Variable quantity of goods, with the possibility of recalculating the total amount through js
3. Noticeable button "Checkout"

All other elements of interaction with the client, such as information about the delivery address, payment method, and other ryushechek may vary in different IM. This post is not about that.
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And now the challenge

Suppose all of the above items are present in IM. The phone is in an accessible place (footer and the “about us” page). Information about the methods of delivery and payment, terms in the top menu. How to minimize calls to order? How to teach people to use the information provided by the system?

One gets the persistent feeling that we do not have the so-called “culture of use” of MI. My guesses:

1. People do not trust the "Internet"
2. Prefer live chat
3. Unclear stock availability
4. Not all delivery and payment details are reflected on the site, or they are hard to find for the buyer.
5. Force majeure

Obviously, removing the phone number from the site would be the wrong decision. But in times of cost optimization, what are the points you see in order to minimize the number of phone calls in IM?

PS I proceeded from the parameters of my store (products for artists). I can give more specific information to those who wish in a personal.

PPS Waiting for a hot discussion :)

PPPS At the request of the curious - the address of our IM in the profile