99.999999% of drivers don't know what "Top Tier" gas is , so as a company, why pay for the licensing when there is absolutely no return on that investment. I'm sure they get way more for their buck as the Official Fuel of NASCAR than they would with "Top Tier"
Googling Sunoco I found this:In 2009, Suncor Energy Inc., marketing under the Sunoco brand in Ontario, merged with Petro-Canada™ As a result, in 2010, Sunoco stations were converted to Petro-Canada stations.
....so that is where all our Sunoco stations went lol