If you have ever had No Flavor Ice Cream [used to be sold to Soda Bars for Making flavored Milkshakes] You know that Vanilla is a Definite Flavor.
Unfortunately I find it hard to find places that still make real Milkshakes.
I haven't had that yet, but I've made ice cream from historical recipes with just cream, sugar syrup and milk, and there is a definite difference. The problem is, the difference between vanilla ice cream and plain ice cream is no greater than that between vanilla ice cream and "vanilla" ice cream. Hereabouts, and from what I hear and read that also goes for the USA, vanilla flavouring is often used as a background to other sweet flavourants. In Germany, we have a particularly abominable thing called Vanillinzucker, a sugar infused with artificial vanilline, that gets put into almost every imaginable kind of cake, cookie or custard and has educated generations to taste around vanilla. It's also a fairly unobtrusive and bland taste, tamer than real vanilla and dosed rather low. To many of my friends, their first taste of actual vanilla ice cream or pudding was a bit of a shock. Personally, I suspect that's not too differennt across the pond, though I think there's more of the genuine article and less Better Living Through Chemistry.