10 years back in Chicago, a colleague of mine was shopping for a Honda car. He went to one of the Honda dealerships. The salesman started giving him the standard pitch about the car and then told him that he should buy from him because they are the biggest dealer in Chicagoland and sell more cars than any other dealer. My colleague listened to all this and finally had it – he told the dealer – “I don’t really care how many cars you sell or if you sell the most, I only need one.”
So when a vendor spouts that they are #1 in some field, do you think buyers care? Why not tell them how you can solve their problem better for them than any other vendor – don’t you think that might work? Customers care about their problem being solved, not what your product is called or how many you sell. Yes, they do want to do business with a vendor who is financially strong and who will be around, but just being #1 will not cut it if you don’t have the best solution to back it up. If financial strength or the revenue size was the only metric, then do you think any of the startups that became juggernauts would have had a chance during the early days?
Software Product Manager by Gopal Shenoy 
I think this is a matter of communicating the So What. Being #1 means what for me the customer? Do I get better discounts since you sell more hence you have better price negotiation with the manufacturer? Or does it mean that you will offer the best service since you sell more cars, you probably get more service requests? Or does it mean
Being #1 vendor matters period. It matters more only if you can effectively communicate the value of it to the customer / buyer.