This agrees with my observations. I haven't had a 'road' bike for a few years, but have done many road miles, including fast group rides, on my touring bike with 700X35mm tires. When riding solo there is a tiny difference in speed, but I have no problem keeping up with a group.

Mid last year I changed my rear tire from a sweet and supple Panaracer Pasela to a burlier Specialized tire with 'blackbelt' flat protection and feel like that made more difference than going from road bike to touring bike.